contains 278 rules |
System Settings
[ref]groupContains rules that check correct system settings. |
contains 210 rules |
Installing and Maintaining Software
[ref]groupThe following sections contain information on
security-relevant choices during the initial operating system
installation process and the setup of software
updates. |
contains 15 rules |
System and Software Integrity
[ref]groupSystem and software integrity can be gained by installing antivirus, increasing
system encryption strength with FIPS, verifying installed software, enabling SELinux,
installing an Intrusion Prevention System, etc. However, installing or enabling integrity
checking tools cannot prevent intrusions, but they can detect that an intrusion
may have occurred. Requirements for integrity checking may be highly dependent on
the environment in which the system will be used. Snapshot-based approaches such
as AIDE may induce considerable overhead in the presence of frequent software updates. |
contains 4 rules |
Software Integrity Checking
[ref]groupBoth the AIDE (Advanced Intrusion Detection Environment)
software and the RPM package management system provide
mechanisms for verifying the integrity of installed software.
AIDE uses snapshots of file metadata (such as hashes) and compares these
to current system files in order to detect changes.
The RPM package management system can conduct integrity
checks by comparing information in its metadata database with
files installed on the system. |
contains 2 rules |
Verify Integrity with AIDE
[ref]groupAIDE conducts integrity checks by comparing information about
files with previously-gathered information. Ideally, the AIDE database is
created immediately after initial system configuration, and then again after any
software update. AIDE is highly configurable, with further configuration
information located in /usr/share/doc/aide-VERSION . |
contains 2 rules |
Install AIDE
[ref]ruleThe aide package can be installed with the following command:
$ sudo yum install aide Rationale:The AIDE package must be installed if it is to be available for integrity checking. Identifiers:
CCE-80844-4 References:
BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-002696, CCI-002699, CCI-001744, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, 1034, 1288, 1341, 1417, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, SRG-OS-000363-GPOS-00150, SRG-OS-000445-GPOS-00199, RHEL-08-010359, 1.4.1, SV-251710r809354_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure aide is installed
package:
name: aide
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80844-4
- CJIS-5.10.1.3
- DISA-STIG-RHEL-08-010359
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_aide_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "aide" ; then
yum install -y "aide"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
package --add=aide
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_aide
class install_aide {
package { 'aide':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "aide"
version = "*"
|
Configure Periodic Execution of AIDE
[ref]ruleAt a minimum, AIDE should be configured to run a weekly scan.
To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab :
05 4 * * * root --check
To implement a weekly execution of AIDE at 4:05am using cron, add the following line to /etc/crontab :
05 4 * * 0 root --check
AIDE can be executed periodically through other means; this is merely one example.
The usage of cron's special time codes, such as @daily and
@weekly is acceptable.Rationale:By default, AIDE does not install itself for periodic execution. Periodically
running AIDE is necessary to reveal unexpected changes in installed files.
Unauthorized changes to the baseline configuration could make the system vulnerable
to various attacks or allow unauthorized access to the operating system. Changes to
operating system configurations can have unintended side effects, some of which may
be relevant to security.
Detecting such changes and providing an automated response can help avoid unintended,
negative consequences that could ultimately affect the security state of the operating
system. The operating system's Information Management Officer (IMO)/Information System
Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or
monitoring system trap when there is an unauthorized modification of a configuration item. Identifiers:
CCE-80676-0 References:
BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-001744, CCI-002699, CCI-002702, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, SI-7, SI-7(1), CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201, 1.4.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure AIDE is installed
package:
name: '{{ item }}'
state: present
with_items:
- aide
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80676-0
- CJIS-5.10.1.3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set cron package name - RedHat
set_fact:
cron_pkg_name: cronie
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_os_family == "RedHat" or ansible_os_family == "Suse"
tags:
- CCE-80676-0
- CJIS-5.10.1.3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set cron package name - Debian
set_fact:
cron_pkg_name: cron
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_os_family == "Debian"
tags:
- CCE-80676-0
- CJIS-5.10.1.3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Install cron
package:
name: '{{ cron_pkg_name }}'
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80676-0
- CJIS-5.10.1.3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure Periodic Execution of AIDE
cron:
name: run AIDE check
minute: 5
hour: 4
weekday: 0
user: root
job: /usr/sbin/aide --check
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80676-0
- CJIS-5.10.1.3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "aide" ; then
yum install -y "aide"
fi
if ! grep -q "/usr/sbin/aide --check" /etc/crontab ; then
echo "05 4 * * * root /usr/sbin/aide --check" >> /etc/crontab
else
sed -i '\!^.* --check.*$!d' /etc/crontab
echo "05 4 * * * root /usr/sbin/aide --check" >> /etc/crontab
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
System Cryptographic Policies
[ref]groupLinux has the capability to centrally configure cryptographic polices. The command
update-crypto-policies is used to set the policy applicable for the various
cryptographic back-ends, such as SSL/TLS libraries. The configured cryptographic
policies will be the default policy used by these backends unless the application
user configures them otherwise. When the system has been configured to use the
centralized cryptographic policies, the administrator is assured that any application
that utilizes the supported backends will follow a policy that adheres to the
configured profile.
Currently the supported backends are:
- GnuTLS library
- OpenSSL library
- NSS library
- OpenJDK
- Libkrb5
- BIND
- OpenSSH
Applications and languages which rely on any of these backends will follow the
system policies as well. Examples are apache httpd, nginx, php, and others. |
contains 2 rules |
Configure System Cryptography Policy
[ref]ruleTo configure the system cryptography policy to use ciphers only from the FUTURE
policy, run the following command:
$ sudo update-crypto-policies --set FUTURE
The rule checks if settings for selected crypto policy are configured as expected. Configuration files in the /etc/crypto-policies/back-ends are either symlinks to correct files provided by Crypto-policies package or they are regular files in case crypto policy customizations are applied.
Crypto policies may be customized by crypto policy modules, in which case it is delimited from the base policy using a colon.Warning:
The system needs to be rebooted for these changes to take effect. Warning:
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process. Rationale:Centralized cryptographic policies simplify applying secure ciphers across an operating system and
the applications that run on that operating system. Use of weak or untested encryption algorithms
undermines the purposes of utilizing encryption to protect data. Identifiers:
CCE-80935-0 References:
164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.312(e)(1), 164.312(e)(2)(ii), 1446, CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, SC-12(2), SC-12(3), FCS_COP.1(1), FCS_COP.1(2), FCS_COP.1(3), FCS_COP.1(4), FCS_CKM.1, FCS_CKM.2, FCS_TLSC_EXT.1, SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, RHEL-08-010020, 1.10, 1.11, SV-230223r792855_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_system_crypto_policy # promote to variable
set_fact:
var_system_crypto_policy: !!str FUTURE
tags:
- always
- name: Configure System Cryptography Policy
lineinfile:
path: /etc/crypto-policies/config
regexp: ^(?!#)(\S+)$
line: '{{ var_system_crypto_policy }}'
create: true
tags:
- CCE-80935-0
- DISA-STIG-RHEL-08-010020
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-12(2)
- NIST-800-53-SC-12(3)
- NIST-800-53-SC-13
- configure_crypto_policy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- name: Verify that Crypto Policy is Set (runtime)
command: /usr/bin/update-crypto-policies --set {{ var_system_crypto_policy }}
tags:
- CCE-80935-0
- DISA-STIG-RHEL-08-010020
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-12(2)
- NIST-800-53-SC-12(3)
- NIST-800-53-SC-13
- configure_crypto_policy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
var_system_crypto_policy='FUTURE'
stderr_of_call=$(update-crypto-policies --set ${var_system_crypto_policy} 2>&1 > /dev/null)
rc=$?
if test "$rc" = 127; then
echo "$stderr_of_call" >&2
echo "Make sure that the script is installed on the remediated system." >&2
echo "See output of the 'dnf provides update-crypto-policies' command" >&2
echo "to see what package to (re)install" >&2
false # end with an error code
elif test "$rc" != 0; then
echo "Error invoking the update-crypto-policies script: $stderr_of_call" >&2
false # end with an error code
fi
|
Configure SSH to use System Crypto Policy
[ref]ruleCrypto Policies provide a centralized control over crypto algorithms usage of many packages.
SSH is supported by crypto policy, but the SSH configuration may be
set up to ignore it.
To check that Crypto Policies settings are configured correctly, ensure that
the CRYPTO_POLICY variable is either commented or not set at all
in the /etc/sysconfig/sshd . Rationale:Overriding the system crypto policy makes the behavior of the SSH service violate expectations,
and makes system configuration more fragmented. Identifiers:
CCE-80939-2 References:
164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.312(e)(1), 164.312(e)(2)(ii), CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, SRG-OS-000250-GPOS-00093, RHEL-08-010287, 5.2.20, SV-244526r809334_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Configure SSH to use System Crypto Policy
lineinfile:
dest: /etc/sysconfig/sshd
state: absent
regexp: ^\s*(?i)CRYPTO_POLICY.*$
tags:
- CCE-80939-2
- DISA-STIG-RHEL-08-010287
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-13
- configure_ssh_crypto_policy
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
Remediation Shell script: (show)
SSH_CONF="/etc/sysconfig/sshd"
sed -i "/^\s*CRYPTO_POLICY.*$/Id" $SSH_CONF
|
Disk Partitioning
[ref]groupTo ensure separation and protection of data, there
are top-level system directories which should be placed on their
own physical partition or logical volume. The installer's default
partitioning scheme creates separate logical volumes for
/ , /boot , and swap .
- If starting with any of the default layouts, check the box to
\"Review and modify partitioning.\" This allows for the easy creation
of additional logical volumes inside the volume group already
created, though it may require making
/ 's logical volume smaller to
create space. In general, using logical volumes is preferable to
using partitions because they can be more easily adjusted
later. - If creating a custom layout, create the partitions mentioned in
the previous paragraph (which the installer will require anyway),
as well as separate ones described in the following sections.
If a system has already been installed, and the default
partitioning
scheme was used, it is possible but nontrivial to
modify it to create separate logical volumes for the directories
listed above. The Logical Volume Manager (LVM) makes this possible.
See the LVM HOWTO at
http://tldp.org/HOWTO/LVM-HOWTO/
for more detailed information on LVM. |
contains 6 rules |
Ensure /home Located On Separate Partition
[ref]ruleIf user home directories will be stored locally, create a separate partition
for /home at installation time (or migrate it later using LVM). If
/home will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later. Rationale:Ensuring that /home is mounted on its own partition enables the
setting of more restrictive mount options, and also helps ensure that
users cannot trivially fill partitions used for log or audit data storage. Identifiers:
CCE-81044-0 References:
BP28(R12), 12, 15, 8, APO13.01, DSS05.02, CCI-000366, CCI-001208, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, CM-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-010800, 1.1.13, SV-230328r627750_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /home
Remediation script: (show)
[[customizations.filesystem]]
mountpoint = "/home"
size = 1073741824
|
Ensure /tmp Located On Separate Partition
[ref]ruleThe /tmp directory is a world-writable directory used
for temporary file storage. Ensure it has its own partition or
logical volume at installation time, or migrate it using LVM. Rationale:The /tmp partition is used as temporary storage by many programs.
Placing /tmp in its own partition enables the setting of more
restrictive mount options, which can help protect programs which use it. Identifiers:
CCE-80851-9 References:
BP28(R12), 12, 15, 8, APO13.01, DSS05.02, CCI-000366, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, CM-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-010543, 1.1.2, SV-230295r627750_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /tmp
Remediation script: (show)
[[customizations.filesystem]]
mountpoint = "/tmp"
size = 1073741824
|
Ensure /var Located On Separate Partition
[ref]ruleThe /var directory is used by daemons and other system
services to store frequently-changing data. Ensure that /var has its own partition
or logical volume at installation time, or migrate it using LVM. Rationale:Ensuring that /var is mounted on its own partition enables the
setting of more restrictive mount options. This helps protect
system services such as daemons or other programs which use it.
It is not uncommon for the /var directory to contain
world-writable directories installed by other software packages. Identifiers:
CCE-80852-7 References:
BP28(R12), 12, 15, 8, APO13.01, DSS05.02, CCI-000366, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, CM-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, SRG-OS-000341-VMM-001220, RHEL-08-010540, 1.1.6, SV-230292r627750_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var
Remediation script: (show)
[[customizations.filesystem]]
mountpoint = "/var"
size = 3221225472
|
Ensure /var/log Located On Separate Partition
[ref]ruleSystem logs are stored in the /var/log directory.
Ensure that /var/log has its own partition or logical
volume at installation time, or migrate it using LVM. Rationale:Placing /var/log in its own partition
enables better separation between log files
and other files in /var/ . Identifiers:
CCE-80853-5 References:
BP28(R12), BP28(R47), 1, 12, 14, 15, 16, 3, 5, 6, 8, APO11.04, APO13.01, BAI03.05, DSS05.02, DSS05.04, DSS05.07, MEA02.01, CCI-000366, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, CIP-007-3 R6.5, CM-6(a), AU-4, SC-5(2), PR.PT-1, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-010541, 1.1.11, SV-230293r627750_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/log
Remediation script: (show)
[[customizations.filesystem]]
mountpoint = "/var/log"
size = 5368709120
|
Ensure /var/log/audit Located On Separate Partition
[ref]ruleAudit logs are stored in the /var/log/audit directory.
Ensure that /var/log/audit has its own partition or logical
volume at installation time, or migrate it using LVM.
Make absolutely certain that it is large enough to store all
audit logs that will be created by the auditing daemon. Rationale:Placing /var/log/audit in its own partition
enables better separation between audit files
and other files, and helps ensure that
auditing cannot be halted due to the partition running out
of space. Identifiers:
CCE-80854-3 References:
BP28(R43), 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 8, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.02, DSS05.04, DSS05.07, MEA02.01, CCI-000366, CCI-001849, 164.312(a)(2)(ii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.2, SR 7.6, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.17.2.1, CIP-007-3 R6.5, CM-6(a), AU-4, SC-5(2), PR.DS-4, PR.PT-1, PR.PT-4, SRG-OS-000341-GPOS-00132, SRG-OS-000480-GPOS-00227, SRG-OS-000341-VMM-001220, RHEL-08-010542, 1.1.12, SV-230294r627750_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/log/audit
Remediation script: (show)
[[customizations.filesystem]]
mountpoint = "/var/log/audit"
size = 10737418240
|
Ensure /var/tmp Located On Separate Partition
[ref]ruleThe /var/tmp directory is a world-writable directory used
for temporary file storage. Ensure it has its own partition or
logical volume at installation time, or migrate it using LVM. Rationale:The /var/tmp partition is used as temporary storage by many programs.
Placing /var/tmp in its own partition enables the setting of more
restrictive mount options, which can help protect programs which use it. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/tmp
Remediation script: (show)
[[customizations.filesystem]]
mountpoint = "/var/tmp"
size = 1073741824
|
GNOME Desktop Environment
[ref]groupGNOME is a graphical desktop environment bundled with many Linux distributions that
allow users to easily interact with the operating system graphically rather than
textually. The GNOME Graphical Display Manager (GDM) provides login, logout, and user
switching contexts as well as display server management.
GNOME is developed by the GNOME Project and is considered the default
Red Hat Graphical environment.
For more information on GNOME and the GNOME Project, see https://www.gnome.org. |
contains 1 rule |
Make sure that the dconf databases are up-to-date with regards to respective keyfiles
[ref]ruleBy default, DConf uses a binary database as a data backend.
The system-level database is compiled from keyfiles in the /etc/dconf/db/
directory by the dconf update command. More specifically, content present
in the following directories:
/etc/dconf/db/gdm.d
/etc/dconf/db/local.d Rationale:Unlike text-based keyfiles, the binary database is impossible to check by OVAL.
Therefore, in order to evaluate dconf configuration, both have to be true at the same time -
configuration files have to be compliant, and the database needs to be more recent than those keyfiles,
which gives confidence that it reflects them. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Sudo , which stands for "su 'do'", provides the ability to delegate authority
to certain users, groups of users, or system administrators. When configured for system
users and/or groups, Sudo can allow a user or group to execute privileged commands
that normally only root is allowed to execute.
For more information on Sudo and addition Sudo configuration options, see
https://www.sudo.ws.
|
contains 3 rules |
Install sudo Package
[ref]ruleThe sudo package can be installed with the following command:
$ sudo yum install sudo Rationale:sudo is a program designed to allow a system administrator to give
limited root privileges to users and log root activity. The basic philosophy
is to give as few privileges as possible but still allow system users to
get their work done. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure sudo is installed
package:
name: sudo
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82214-8
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_sudo_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "sudo" ; then
yum install -y "sudo"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
package --add=sudo
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_sudo
class install_sudo {
package { 'sudo':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "sudo"
version = "*"
|
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty
[ref]ruleThe sudo use_pty tag, when specified, will only execute sudo
commands from users logged in to a real tty.
This should be enabled by making sure that the use_pty tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Requiring that sudo commands be run in a pseudo-terminal can prevent an attacker from retaining
access to the user's terminal after the main program has finished executing. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure use_pty is enabled in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults.*\buse_pty\b.*$
line: Defaults use_pty
validate: /usr/sbin/visudo -cf %s
tags:
- CCE-83798-9
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_use_pty
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults.*\buse_pty\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option use_pty
echo "Defaults use_pty" >> /etc/sudoers
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
|
Ensure Sudo Logfile Exists - sudo logfile
[ref]ruleA custom log sudo file can be configured with the 'logfile' tag. This rule configures
a sudo custom logfile at the default location suggested by CIS, which uses
/var/log/sudo.log. Rationale:A sudo log file simplifies auditing of sudo commands. Identifiers:
CCE-83601-5 References:
1.3.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sudo_logfile # promote to variable
set_fact:
var_sudo_logfile: !!str /var/log/sudo.log
tags:
- always
- name: Ensure logfile is enabled with the appropriate value in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults\s(.*)\blogfile=[-]?\w+\b(.*)$
line: Defaults \1logfile={{ var_sudo_logfile }}\2
validate: /usr/sbin/visudo -cf %s
backrefs: true
register: edit_sudoers_logfile_option
tags:
- CCE-83601-5
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- sudo_custom_logfile
- name: Enable logfile option with appropriate value in /etc/sudoers
lineinfile:
path: /etc/sudoers
line: Defaults logfile={{ var_sudo_logfile }}
validate: /usr/sbin/visudo -cf %s
when: edit_sudoers_logfile_option is defined and not edit_sudoers_logfile_option.changed
tags:
- CCE-83601-5
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- sudo_custom_logfile
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
var_sudo_logfile='/var/log/sudo.log'
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults.*\blogfile=("(?:\\"|\\\\|[^"\\\n])*"\B|[^"](?:(?:\\,|\\"|\\ |\\\\|[^", \\\n])*)\b)\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option logfile
echo "Defaults logfile=${var_sudo_logfile}" >> /etc/sudoers
else
# sudoers file defines Option logfile, remediate if appropriate value is not set
if ! grep -P "^[\s]*Defaults.*\blogfile=${var_sudo_logfile}\b.*$" /etc/sudoers; then
sed -Ei "s/(^[\s]*Defaults.*\blogfile=)[-]?\w+(\b.*$)/\1${var_sudo_logfile}\2/" /etc/sudoers
fi
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
|
Updating Software
[ref]groupThe yum command line tool is used to install and
update software packages. The system also provides a graphical
software update tool in the System menu, in the Administration submenu,
called Software Update.
Red Hat Enterprise Linux 8 systems contain an installed software catalog called
the RPM database, which records metadata of installed packages. Consistently using
yum or the graphical Software Update for all software installation
allows for insight into the current inventory of installed software on the system.
|
contains 1 rule |
Ensure gpgcheck Enabled In Main yum Configuration
[ref]ruleThe gpgcheck option controls whether
RPM packages' signatures are always checked prior to installation.
To configure yum to check package signatures before installing
them, ensure the following line appears in /etc/yum.conf in
the [main] section:
gpgcheck=1 Rationale:Changes to any software components can have significant effects on the
overall security of the operating system. This requirement ensures the
software has not been tampered with and that it has been provided by a
trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system
components must be signed with a certificate recognized and approved by the
organization.
Verifying the authenticity of the software prior to installation
validates the integrity of the patch or upgrade received from a vendor.
This ensures the software has not been tampered with and that it has been
provided by a trusted vendor. Self-signed certificates are disallowed by
this requirement. Certificates used to verify the software must be from an
approved Certificate Authority (CA). Identifiers:
CCE-80790-9 References:
BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, SRG-OS-000366-GPOS-00153, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650, RHEL-08-010370, 1.2.4, SV-230264r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80790-9
- CJIS-5.10.4.1
- DISA-STIG-RHEL-08-010370
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- configure_strategy
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- name: Ensure GPG check is globally activated
ini_file:
dest: /etc/yum.conf
section: main
option: gpgcheck
value: 1
no_extra_spaces: true
create: false
when: '"yum" in ansible_facts.packages'
tags:
- CCE-80790-9
- CJIS-5.10.4.1
- DISA-STIG-RHEL-08-010370
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- configure_strategy
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/yum.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^gpgcheck")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^gpgcheck\\>" "/etc/yum.conf"; then
"${sed_command[@]}" "s/^gpgcheck\\>.*/$formatted_output/gi" "/etc/yum.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80790-9"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/yum.conf" >> "/etc/yum.conf"
printf '%s\n' "$formatted_output" >> "/etc/yum.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Account and Access Control
[ref]groupIn traditional Unix security, if an attacker gains
shell access to a certain login account, they can perform any action
or access any file to which that account has access. Therefore,
making it more difficult for unauthorized people to gain shell
access to accounts, particularly to privileged accounts, is a
necessary part of securing a system. This section introduces
mechanisms for restricting access to accounts under
Red Hat Enterprise Linux 8. |
contains 46 rules |
Warning Banners for System Accesses
[ref]groupEach system should expose as little information about
itself as possible.
System banners, which are typically displayed just before a
login prompt, give out information about the service or the host's
operating system. This might include the distribution name and the
system kernel version, and the particular version of a network
service. This information can assist intruders in gaining access to
the system as it can reveal whether the system is running
vulnerable software. Most network services can be configured to
limit what information is displayed.
Many organizations implement security policies that require a
system banner provide notice of the system's ownership, provide
warning to unauthorized users, and remind authorized users of their
consent to monitoring. |
contains 10 rules |
Implement a GUI Warning Banner
[ref]groupIn the default graphical environment, users logging
directly into the system are greeted with a login screen provided
by the GNOME Display Manager (GDM). The warning banner should be
displayed in this graphical environment for these users.
The following sections describe how to configure the GDM login
banner. |
contains 2 rules |
Enable GNOME3 Login Warning Banner
[ref]ruleIn the default graphical environment, displaying a login warning banner
in the GNOME Display Manager's login screen can be enabled on the login
screen by setting banner-message-enable to true .
To enable, add or edit banner-message-enable to
/etc/dconf/db/gdm.d/00-security-settings . For example:
[org/gnome/login-screen]
banner-message-enable=true
Once the setting has been added, add a lock to
/etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/login-screen/banner-message-enable
After the settings have been set, run dconf update .
The banner text must also be set.Rationale:Display of a standardized and approved use notification before granting access to the operating system
ensures privacy and security notification verbiage used is consistent with applicable federal laws,
Executive Orders, directives, policies, regulations, standards, and guidance.
For U.S. Government systems, system use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not exist. Identifiers:
CCE-80768-5 References:
1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(b), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088, RHEL-08-010049, 1.8.2, SV-244519r743806_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80768-5
- DISA-STIG-RHEL-08-010049
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(b)
- NIST-800-53-AC-8(c)
- dconf_gnome_banner_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Enable GNOME3 Login Warning Banner
ini_file:
dest: /etc/dconf/db/gdm.d/00-security-settings
section: org/gnome/login-screen
option: banner-message-enable
value: 'true'
create: true
no_extra_spaces: true
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-80768-5
- DISA-STIG-RHEL-08-010049
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(b)
- NIST-800-53-AC-8(c)
- dconf_gnome_banner_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME banner-message-enabled
lineinfile:
path: /etc/dconf/db/gdm.d/locks/00-security-settings-lock
regexp: ^/org/gnome/login-screen/banner-message-enable$
line: /org/gnome/login-screen/banner-message-enable
create: true
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-80768-5
- DISA-STIG-RHEL-08-010049
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(b)
- NIST-800-53-AC-8(c)
- dconf_gnome_banner_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-80768-5
- DISA-STIG-RHEL-08-010049
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(b)
- NIST-800-53-AC-8(c)
- dconf_gnome_banner_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm; then
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/gdm.d/00-security-settings"
DBDIR="/etc/dconf/db/gdm.d"
mkdir -p "${DBDIR}"
if [ "${#SETTINGSFILES[@]}" -eq 0 ]
then
[ ! -z ${DCONFFILE} ] || echo "" >> ${DCONFFILE}
printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
printf '%s=%s\n' "banner-message-enable" "true" >> ${DCONFFILE}
else
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
if grep -q "^\\s*banner-message-enable\\s*=" "${SETTINGSFILES[@]}"
then
sed -i "s/\\s*banner-message-enable\\s*=\\s*.*/banner-message-enable=${escaped_value}/g" "${SETTINGSFILES[@]}"
else
sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-enable=${escaped_value}" "${SETTINGSFILES[@]}"
fi
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/login-screen/banner-message-enable$" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/gdm.d/locks"
mkdir -p "${LOCKSFOLDER}"
if [[ -z "${LOCKFILES}" ]]
then
echo "/org/gnome/login-screen/banner-message-enable" >> "/etc/dconf/db/gdm.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set the GNOME3 Login Warning Banner Text
[ref]ruleIn the default graphical environment, configuring the login warning banner text
in the GNOME Display Manager's login screen can be configured on the login
screen by setting banner-message-text to 'APPROVED_BANNER'
where APPROVED_BANNER is the approved banner for your environment.
To enable, add or edit banner-message-text to
/etc/dconf/db/gdm.d/00-security-settings . For example:
[org/gnome/login-screen]
banner-message-text='APPROVED_BANNER'
Once the setting has been added, add a lock to
/etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/login-screen/banner-message-text
After the settings have been set, run dconf update .
When entering a warning banner that spans several lines, remember
to begin and end the string with ' and use \n for new lines.Rationale:An appropriate warning message reinforces policy awareness during the logon
process and facilitates possible legal action against attackers. Identifiers:
CCE-80770-1 References:
1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088, RHEL-08-010050, 1.8.2, SV-230226r743916_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80770-1
- DISA-STIG-RHEL-08-010050
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: XCCDF Value login_banner_text # promote to variable
set_fact:
login_banner_text: !!str ^(Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.|^(?!.*(\\|fedora|rhel|sle|ubuntu)).*)$
tags:
- always
- name: Set the GNOME3 Login Warning Banner Text
file:
path: /etc/dconf/db/{{ item }}
owner: root
group: root
mode: 493
state: directory
with_items:
- gdm.d
- gdm.d/locks
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-80770-1
- DISA-STIG-RHEL-08-010050
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Set the GNOME3 Login Warning Banner Text
file:
path: /etc/dconf/db/gdm.d/{{ item }}
owner: root
group: root
mode: 420
state: touch
with_items:
- 00-security-settings
- locks/00-security-settings-lock
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-80770-1
- DISA-STIG-RHEL-08-010050
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Set the GNOME3 Login Warning Banner Text
ini_file:
dest: /etc/dconf/db/gdm.d/00-security-settings
section: org/gnome/login-screen
option: banner-message-text
value: '''{{ login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*\.)\|.*\)$",
"\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
"(n)*") | regex_replace("\\", "") | regex_replace("\(n\)\*", "\\n") }}'''
create: true
no_extra_spaces: true
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-80770-1
- DISA-STIG-RHEL-08-010050
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of the GNOME3 Login Warning Banner Text
lineinfile:
path: /etc/dconf/db/gdm.d/locks/00-security-settings-lock
regexp: ^/org/gnome/login-screen/banner-message-text$
line: /org/gnome/login-screen/banner-message-text
create: true
state: present
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-80770-1
- DISA-STIG-RHEL-08-010050
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-80770-1
- DISA-STIG-RHEL-08-010050
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm; then
login_banner_text='^(Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.|^(?!.*(\\|fedora|rhel|sle|ubuntu)).*)$'
# Multiple regexes transform the banner regex into a usable banner
# 0 - Remove anchors around the banner text
login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
# 1 - Keep only the first banners if there are multiple
# (dod_banners contains the long and short banner)
login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\.\)|.*)$/\1/g')
# 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
# 3 - Adds newline "tokens". (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "(n)*")
login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\\\n)+)/(n)*/g')
# 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
# 5 - Removes the newline "token." (Transforms them into newline escape sequences "\n").
# ( Needs to be done after 4, otherwise the escapce sequence will become just "n".
login_banner_text=$(echo "$login_banner_text" | sed 's/(n)\*/\\n/g')
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/gdm.d/00-security-settings"
DBDIR="/etc/dconf/db/gdm.d"
mkdir -p "${DBDIR}"
if [ "${#SETTINGSFILES[@]}" -eq 0 ]
then
[ ! -z ${DCONFFILE} ] || echo "" >> ${DCONFFILE}
printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
printf '%s=%s\n' "banner-message-text" "'${login_banner_text}'" >> ${DCONFFILE}
else
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "'${login_banner_text}'")"
if grep -q "^\\s*banner-message-text\\s*=" "${SETTINGSFILES[@]}"
then
sed -i "s/\\s*banner-message-text\\s*=\\s*.*/banner-message-text=${escaped_value}/g" "${SETTINGSFILES[@]}"
else
sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-text=${escaped_value}" "${SETTINGSFILES[@]}"
fi
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/login-screen/banner-message-text$" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/gdm.d/locks"
mkdir -p "${LOCKSFOLDER}"
if [[ -z "${LOCKFILES}" ]]
then
echo "/org/gnome/login-screen/banner-message-text" >> "/etc/dconf/db/gdm.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Modify the System Login Banner
[ref]rule
To configure the system login banner edit /etc/issue . Replace the
default text with a message compliant with the local site policy or a legal
disclaimer.
The DoD required text is either:
You are accessing a U.S. Government (USG) Information System (IS) that
is provided for USG-authorized use only. By using this IS (which includes
any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS
for purposes including, but not limited to, penetration testing, COMSEC
monitoring, network operations and defense, personnel misconduct (PM), law
enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private,
are subject to routine monitoring, interception, and search, and may be
disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access
controls) to protect USG interests -- not for your personal benefit or
privacy.
-Notwithstanding the above, using this IS does not constitute consent
to PM, LE or CI investigative searching or monitoring of the content of
privileged communications, or work product, related to personal
representation or services by attorneys, psychotherapists, or clergy, and
their assistants. Such communications and work product are private and
confidential. See User Agreement for details.
OR:
I've read & consent to terms in IS user agreem't. Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
System use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not
exist. Identifiers:
CCE-80763-6 References:
1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088, SRG-OS-000023-VMM-000060, SRG-OS-000024-VMM-000070, RHEL-08-010060, 1.8.1.2, SV-230227r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: XCCDF Value login_banner_text # promote to variable
set_fact:
login_banner_text: !!str ^(Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.|^(?!.*(\\|fedora|rhel|sle|ubuntu)).*)$
tags:
- always
- name: Modify the System Login Banner - ensure correct banner
copy:
dest: /etc/issue
content: '{{ login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*\.)\|.*\)$",
"\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
"\n") | regex_replace("\\", "") | wordwrap() }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80763-6
- DISA-STIG-RHEL-08-010060
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- banner_etc_issue
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
login_banner_text='^(Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.|^(?!.*(\\|fedora|rhel|sle|ubuntu)).*)$'
# Multiple regexes transform the banner regex into a usable banner
# 0 - Remove anchors around the banner text
login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
# 1 - Keep only the first banners if there are multiple
# (dod_banners contains the long and short banner)
login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\.\)|.*)$/\1/g')
# 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
# 3 - Adds newlines. (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "\n")
login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\\\n)+)/\n/g')
# 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
formatted=$(echo "$login_banner_text" | fold -sw 80)
cat <<EOF >/etc/issue
$formatted
EOF
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Modify the System Message of the Day Banner
[ref]ruleTo configure the system message banner edit /etc/motd . Replace the
default text with a message compliant with the local site policy or a legal
disclaimer.
The DoD required text is either:
You are accessing a U.S. Government (USG) Information System (IS) that
is provided for USG-authorized use only. By using this IS (which includes
any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS
for purposes including, but not limited to, penetration testing, COMSEC
monitoring, network operations and defense, personnel misconduct (PM), law
enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private,
are subject to routine monitoring, interception, and search, and may be
disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access
controls) to protect USG interests -- not for your personal benefit or
privacy.
-Notwithstanding the above, using this IS does not constitute consent
to PM, LE or CI investigative searching or monitoring of the content of
privileged communications, or work product, related to personal
representation or services by attorneys, psychotherapists, or clergy, and
their assistants. Such communications and work product are private and
confidential. See User Agreement for details.
OR:
I've read & consent to terms in IS user agreem't. Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
System use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not
exist. Identifiers:
CCE-83496-0 References:
1.8.1.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: XCCDF Value login_banner_text # promote to variable
set_fact:
login_banner_text: !!str ^(Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.|^(?!.*(\\|fedora|rhel|sle|ubuntu)).*)$
tags:
- always
- name: Modify the System Message of the Day Banner - ensure correct banner
copy:
dest: /etc/motd
content: '{{ login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*\.)\|.*\)$",
"\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
"\n") | regex_replace("\\", "") | wordwrap() }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83496-0
- banner_etc_motd
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
login_banner_text='^(Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.|^(?!.*(\\|fedora|rhel|sle|ubuntu)).*)$'
# Multiple regexes transform the banner regex into a usable banner
# 0 - Remove anchors around the banner text
login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
# 1 - Keep only the first banners if there are multiple
# (dod_banners contains the long and short banner)
login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\.\)|.*)$/\1/g')
# 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
# 3 - Adds newlines. (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "\n")
login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\\\n)+)/\n/g')
# 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
formatted=$(echo "$login_banner_text" | fold -sw 80)
cat <<EOF >/etc/motd
$formatted
EOF
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Ownership of System Login Banner
[ref]rule
To properly set the group owner of /etc/issue , run the command:
$ sudo chgrp root /etc/issue Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper group ownership will ensure that only root user can modify the banner. Identifiers:
CCE-83708-8 References:
1.8.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/issue
stat:
path: /etc/issue
register: file_exists
tags:
- CCE-83708-8
- configure_strategy
- file_groupowner_etc_issue
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/issue
file:
path: /etc/issue
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83708-8
- configure_strategy
- file_groupowner_etc_issue
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/issue
|
Verify Group Ownership of Message of the Day Banner
[ref]rule
To properly set the group owner of /etc/motd , run the command:
$ sudo chgrp root /etc/motd Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper group ownership will ensure that only root user can modify the banner. Identifiers:
CCE-83728-6 References:
1.8.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/motd
stat:
path: /etc/motd
register: file_exists
tags:
- CCE-83728-6
- configure_strategy
- file_groupowner_etc_motd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/motd
file:
path: /etc/motd
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83728-6
- configure_strategy
- file_groupowner_etc_motd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/motd
|
Verify ownership of System Login Banner
[ref]rule
To properly set the owner of /etc/issue , run the command:
$ sudo chown root /etc/issue Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper ownership will ensure that only root user can modify the banner. Identifiers:
CCE-83718-7 References:
1.8.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/issue
stat:
path: /etc/issue
register: file_exists
tags:
- CCE-83718-7
- configure_strategy
- file_owner_etc_issue
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/issue
file:
path: /etc/issue
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83718-7
- configure_strategy
- file_owner_etc_issue
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/issue
|
Verify ownership of Message of the Day Banner
[ref]rule
To properly set the owner of /etc/motd , run the command:
$ sudo chown root /etc/motd Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper ownership will ensure that only root user can modify the banner. Identifiers:
CCE-83738-5 References:
1.8.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/motd
stat:
path: /etc/motd
register: file_exists
tags:
- CCE-83738-5
- configure_strategy
- file_owner_etc_motd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/motd
file:
path: /etc/motd
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83738-5
- configure_strategy
- file_owner_etc_motd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/motd
|
Verify permissions on System Login Banner
[ref]rule
To properly set the permissions of /etc/issue , run the command:
$ sudo chmod 0644 /etc/issue Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper permissions will ensure that only root user can modify the banner. Identifiers:
CCE-83348-3 References:
1.8.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/issue
stat:
path: /etc/issue
register: file_exists
tags:
- CCE-83348-3
- configure_strategy
- file_permissions_etc_issue
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/issue
file:
path: /etc/issue
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83348-3
- configure_strategy
- file_permissions_etc_issue
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/issue
|
Verify permissions on Message of the Day Banner
[ref]rule
To properly set the permissions of /etc/motd , run the command:
$ sudo chmod 0644 /etc/motd Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper permissions will ensure that only root user can modify the banner. Identifiers:
CCE-83338-4 References:
1.8.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/motd
stat:
path: /etc/motd
register: file_exists
tags:
- CCE-83338-4
- configure_strategy
- file_permissions_etc_motd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/motd
file:
path: /etc/motd
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83338-4
- configure_strategy
- file_permissions_etc_motd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/motd
|
Protect Accounts by Configuring PAM
[ref]groupPAM, or Pluggable Authentication Modules, is a system
which implements modular authentication for Linux programs. PAM provides
a flexible and configurable architecture for authentication, and it should be configured
to minimize exposure to unnecessary risk. This section contains
guidance on how to accomplish that.
PAM is implemented as a set of shared objects which are
loaded and invoked whenever an application wishes to authenticate a
user. Typically, the application must be running as root in order
to take advantage of PAM, because PAM's modules often need to be able
to access sensitive stores of account information, such as /etc/shadow.
Traditional privileged network listeners
(e.g. sshd) or SUID programs (e.g. sudo) already meet this
requirement. An SUID root application, userhelper, is provided so
that programs which are not SUID or privileged themselves can still
take advantage of PAM.
PAM looks in the directory /etc/pam.d for
application-specific configuration information. For instance, if
the program login attempts to authenticate a user, then PAM's
libraries follow the instructions in the file /etc/pam.d/login
to determine what actions should be taken.
One very important file in /etc/pam.d is
/etc/pam.d/system-auth . This file, which is included by
many other PAM configuration files, defines 'default' system authentication
measures. Modifying this file is a good way to make far-reaching
authentication changes, for instance when implementing a
centralized authentication service. Warning:
Be careful when making changes to PAM's configuration files.
The syntax for these files is complex, and modifications can
have unexpected consequences. The default configurations shipped
with applications should be sufficient for most users. |
contains 6 rules |
Set Lockouts for Failed Password Attempts
[ref]groupThe pam_faillock PAM module provides the capability to
lock out user accounts after a number of failed login attempts. Its
documentation is available in
/usr/share/doc/pam-VERSION/txts/README.pam_faillock .
Warning:
Locking out user accounts presents the
risk of a denial-of-service attack. The lockout policy
must weigh whether the risk of such a
denial-of-service attack outweighs the benefits of thwarting
password guessing attacks. |
contains 2 rules |
Limit Password Reuse: password-auth
[ref]ruleDo not allow users to reuse recent passwords. This can be accomplished by using the
remember option for the pam_pwhistory PAM module. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report. Rationale:Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user. Identifiers:
CCE-83478-8 References:
1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, CCI-000200, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(e), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.5, SRG-OS-000077-GPOS-00045, SRG-OS-000077-VMM-000440, RHEL-08-020220, 5.4.3, SV-230368r810414_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83478-8
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020220
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_remember # promote to variable
set_fact:
var_password_pam_remember: !!str 5
tags:
- always
- name: XCCDF Value var_password_pam_remember_control_flag # promote to variable
set_fact:
var_password_pam_remember_control_flag: !!str required
tags:
- always
- name: Check for existing pam_pwhistory.so entry
ansible.builtin.lineinfile:
path: /etc/pam.d/password-auth
create: false
regexp: ^password.*pam_pwhistory.so.*
state: absent
check_mode: true
changed_when: false
register: result_pam_pwhistory_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83478-8
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020220
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Check for existing remember parameter entry
ansible.builtin.lineinfile:
path: /etc/pam.d/password-auth
create: false
regexp: ^password.*pam_pwhistory.so.*remember=
state: absent
check_mode: true
changed_when: false
register: result_pam_pwhistory_remember_present
when:
- '"pam" in ansible_facts.packages'
- result_pam_pwhistory_present.found == 1
tags:
- CCE-83478-8
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020220
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Check if system relies on authselect
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83478-8
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020220
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Remediation where authselect tool is present
block:
- name: Check the integrity of the current authselect profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
ignore_errors: true
- name: Informative message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd is success
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because the authselect profile is
not intact.
- It is not recommended to manually edit the PAM files when authselect is
available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Get authselect current profile
ansible.builtin.shell:
cmd: authselect current -r | awk '{ print $1 }'
register: result_authselect_profile
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Define the current authselect profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is match("custom/")
- name: Define the new authselect custom profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: custom/hardening
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is not match("custom/")
- name: Get authselect current features to also enable them in the custom profile
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- name: Check if any custom profile with the same name was already created in
the past
ansible.builtin.stat:
path: /etc/authselect/{{ authselect_custom_profile }}
register: result_authselect_custom_profile_present
changed_when: false
when:
- authselect_current_profile is not match("custom/")
- name: Create a custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b sssd
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure the desired remember value is updated in the custom profile
ansible.builtin.replace:
dest: /etc/authselect/{{ authselect_custom_profile }}/password-auth
regexp: (.*pam_pwhistory.so.*remember=)(\S+)(.*)$
replace: \g<1>{{ var_password_pam_remember }}\g<3>
when:
- result_authselect_profile is not skipped
- result_pam_pwhistory_present.found == 1
- result_pam_pwhistory_remember_present.found == 1
- name: Ensure the remember parameter is included in the custom profile
ansible.builtin.replace:
dest: /etc/authselect/{{ authselect_custom_profile }}/password-auth
regexp: (.*pam_pwhistory.so.*)(?! remember=\S+)(.*)$
replace: \g<1> \g<2> remember={{ var_password_pam_remember }}
when:
- result_authselect_profile is not skipped
- result_pam_pwhistory_present.found == 1
- result_pam_pwhistory_remember_present.found == 0
- name: Ensure the desired control value is updated in the custom profile
ansible.builtin.replace:
dest: /etc/authselect/{{ authselect_custom_profile }}/password-auth
regexp: ^(password\s+)((?:(?:requisite)|(?:required)))(\s+pam_pwhistory\.so\s.*)$
replace: \g<1>{{ var_password_pam_remember_control_flag }}\g<3>
when:
- result_authselect_profile is not skipped
- result_pam_pwhistory_present.found == 1
- name: Ensure the desired configuration is present in the custom profile
ansible.builtin.lineinfile:
dest: /etc/authselect/{{ authselect_custom_profile }}/password-auth
insertafter: ^password.*requisite.*pam_pwquality.so.*
line: password {{ var_password_pam_remember_control_flag }} pam_pwhistory.so
remember={{ var_password_pam_remember }} use_authtok
when:
- result_authselect_profile is not skipped
- result_pam_pwhistory_present.found == 0
- name: Ensure a backup of current authselect profile before selecting the custom
profile
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-pwhistory-hardening.backup
register: result_authselect_backup
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Ensure the custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }} --force
register: result_pam_authselect_select_profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure the custom profile changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-pwhistory-hardening.backup
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CCE-83478-8
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020220
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Remediation where authselect tool is not present and PAM files are directly
edited
block:
- name: Ensure the desired remember value is updated in the custom profile
ansible.builtin.replace:
dest: /etc/pam.d/password-auth
regexp: (.*pam_pwhistory.so.*remember=)(\S+)(.*)$
replace: \g<1>{{ var_password_pam_remember }}\g<3>
when:
- result_pam_pwhistory_present.found == 1
- name: Ensure the remember parameter is included in the custom profile
ansible.builtin.replace:
dest: /etc/pam.d/password-auth
regexp: (.*pam_pwhistory.so.*)(?! remember=\S+)(.*)$
replace: \g<1> \g<2> remember={{ var_password_pam_remember }}
when:
- result_pam_pwhistory_present.found == 1
- result_pam_pwhistory_remember_present.found == 0
- name: Ensure the desired control value is updated in the custom profile
ansible.builtin.replace:
dest: /etc/pam.d/password-auth
regexp: ^(password\s+)((?:(?:requisite)|(?:required)))(\s+pam_pwhistory\.so\s.*)$
replace: \g<1>{{ var_password_pam_remember_control_flag }}\g<3>
when:
- result_pam_pwhistory_present.found == 1
- name: Ensure the desired configuration is present in the custom profile
ansible.builtin.lineinfile:
dest: /etc/pam.d/password-auth
insertafter: ^password.*requisite.*pam_pwquality.so.*
line: password {{ var_password_pam_remember_control_flag }} pam_pwhistory.so
remember={{ var_password_pam_remember }} use_authtok
when:
- result_pam_pwhistory_present.found == 0
when:
- '"pam" in ansible_facts.packages'
- not result_authselect_present.stat.exists
tags:
- CCE-83478-8
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020220
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_remember='5'
var_password_pam_remember_control_flag='required'
# control required is for rhel8, while requisite is for other distros
CONTROL=${var_password_pam_remember_control_flag}
if [ -f /usr/bin/authselect ]; then
if authselect check; then
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# Standard profiles delivered with authselect should not be modified.
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
# Ensure a backup before changing the profile
authselect apply-changes -b --backup=before-pwhistory-hardening.backup
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
fi
# Include the desired configuration in the custom profile
CUSTOM_PASSWORD_AUTH="/etc/authselect/$CURRENT_PROFILE/password-auth"
if grep -q "^password.*pam_pwhistory.so.*" $CUSTOM_PASSWORD_AUTH; then
if ! grep -q "^[^#].*pam_pwhistory.so.*remember=" $CUSTOM_PASSWORD_AUTH; then
sed -i --follow-symlinks "/pam_pwhistory.so/ s/$/ remember=$var_password_pam_remember/" $CUSTOM_PASSWORD_AUTH
else
sed -r -i --follow-symlinks "s/(.*pam_pwhistory.so.*)(remember=[[:digit:]]+)\s(.*)/\1remember=$var_password_pam_remember \3/g" $CUSTOM_PASSWORD_AUTH
fi
# Ensure correct control is being used per os requirement
if ! grep -q "^password.*$CONTROL.*pam_pwhistory.so.*" $CUSTOM_PASSWORD_AUTH; then
# Replace incorrect value
sed -r -i --follow-symlinks "s/(^password.*)(required|requisite)(.*pam_pwhistory\.so.*)$/\1$CONTROL\3/" $CUSTOM_PASSWORD_AUTH
fi
else
sed -i --follow-symlinks "/^password.*requisite.*pam_pwquality.so/a password $CONTROL pam_pwhistory.so remember=$var_password_pam_remember use_authtok" $CUSTOM_PASSWORD_AUTH
fi
authselect apply-changes -b --backup=after-pwhistory-hardening.backup
else
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because the authselect profile is not intact.
It is not recommended to manually edit the PAM files when authselect is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
false
fi
else
pamFile="/etc/pam.d/password-auth"
# is 'password required|requisite pam_pwhistory.so' here?
if grep -q "^password.*pam_pwhistory.so.*" $pamFile; then
# is the remember option set?
option=$(sed -rn 's/^(.*pam_pwhistory\.so.*)(remember=[0-9]+)(.*)$/\2/p' $pamFile)
if [[ -z $option ]]; then
# option is not set, append to module
sed -i --follow-symlinks "/pam_pwhistory.so/ s/$/ remember=$var_password_pam_remember/" $pamFile
else
# option is set, replace value
sed -r -i --follow-symlinks "s/^(.*pam_pwhistory\.so.*)(remember=[0-9]+)(.*)$/\1remember=$var_password_pam_remember\3/" $pamFile
fi
# ensure correct control is being used per os requirement
if ! grep -q "^password.*$CONTROL.*pam_pwhistory.so.*" $pamFile; then
#replace incorrect value
sed -r -i --follow-symlinks "s/(^password.*)(required|requisite)(.*pam_pwhistory\.so.*)$/\1$CONTROL\3/" $pamFile
fi
else
# no 'password required|requisite pam_pwhistory.so', add it
sed -i --follow-symlinks "/^password.*pam_unix.so.*/i password $CONTROL pam_pwhistory.so use_authtok remember=$var_password_pam_remember" $pamFile
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Limit Password Reuse: system-auth
[ref]ruleDo not allow users to reuse recent passwords. This can be accomplished by using the
remember option for the pam_pwhistory PAM module. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report. Rationale:Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user. Identifiers:
CCE-83480-4 References:
1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, CCI-000200, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(e), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.5, SRG-OS-000077-GPOS-00045, SRG-OS-000077-VMM-000440, RHEL-08-020221, 5.4.3, SV-251717r810415_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83480-4
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020221
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_remember # promote to variable
set_fact:
var_password_pam_remember: !!str 5
tags:
- always
- name: XCCDF Value var_password_pam_remember_control_flag # promote to variable
set_fact:
var_password_pam_remember_control_flag: !!str required
tags:
- always
- name: Check for existing pam_pwhistory.so entry
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
create: false
regexp: ^password.*pam_pwhistory.so.*
state: absent
check_mode: true
changed_when: false
register: result_pam_pwhistory_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83480-4
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020221
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Check for existing remember parameter entry
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
create: false
regexp: ^password.*pam_pwhistory.so.*remember=
state: absent
check_mode: true
changed_when: false
register: result_pam_pwhistory_remember_present
when:
- '"pam" in ansible_facts.packages'
- result_pam_pwhistory_present.found == 1
tags:
- CCE-83480-4
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020221
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Check if system relies on authselect
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83480-4
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020221
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Remediation where authselect tool is present
block:
- name: Check the integrity of the current authselect profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
ignore_errors: true
- name: Informative message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd is success
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because the authselect profile is
not intact.
- It is not recommended to manually edit the PAM files when authselect is
available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Get authselect current profile
ansible.builtin.shell:
cmd: authselect current -r | awk '{ print $1 }'
register: result_authselect_profile
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Define the current authselect profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is match("custom/")
- name: Define the new authselect custom profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: custom/hardening
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is not match("custom/")
- name: Get authselect current features to also enable them in the custom profile
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- name: Check if any custom profile with the same name was already created in
the past
ansible.builtin.stat:
path: /etc/authselect/{{ authselect_custom_profile }}
register: result_authselect_custom_profile_present
changed_when: false
when:
- authselect_current_profile is not match("custom/")
- name: Create a custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b sssd
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure the desired remember value is updated in the custom profile
ansible.builtin.replace:
dest: /etc/authselect/{{ authselect_custom_profile }}/system-auth
regexp: (.*pam_pwhistory.so.*remember=)(\S+)(.*)$
replace: \g<1>{{ var_password_pam_remember }}\g<3>
when:
- result_authselect_profile is not skipped
- result_pam_pwhistory_present.found == 1
- result_pam_pwhistory_remember_present.found == 1
- name: Ensure the remember parameter is included in the custom profile
ansible.builtin.replace:
dest: /etc/authselect/{{ authselect_custom_profile }}/system-auth
regexp: (.*pam_pwhistory.so.*)(?! remember=\S+)(.*)$
replace: \g<1> \g<2> remember={{ var_password_pam_remember }}
when:
- result_authselect_profile is not skipped
- result_pam_pwhistory_present.found == 1
- result_pam_pwhistory_remember_present.found == 0
- name: Ensure the desired control value is updated in the custom profile
ansible.builtin.replace:
dest: /etc/authselect/{{ authselect_custom_profile }}/system-auth
regexp: ^(password\s+)((?:(?:requisite)|(?:required)))(\s+pam_pwhistory\.so\s.*)$
replace: \g<1>{{ var_password_pam_remember_control_flag }}\g<3>
when:
- result_authselect_profile is not skipped
- result_pam_pwhistory_present.found == 1
- name: Ensure the desired configuration is present in the custom profile
ansible.builtin.lineinfile:
dest: /etc/authselect/{{ authselect_custom_profile }}/system-auth
insertafter: ^password.*requisite.*pam_pwquality.so.*
line: password {{ var_password_pam_remember_control_flag }} pam_pwhistory.so
remember={{ var_password_pam_remember }} use_authtok
when:
- result_authselect_profile is not skipped
- result_pam_pwhistory_present.found == 0
- name: Ensure a backup of current authselect profile before selecting the custom
profile
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-pwhistory-hardening.backup
register: result_authselect_backup
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Ensure the custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }} --force
register: result_pam_authselect_select_profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure the custom profile changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-pwhistory-hardening.backup
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CCE-83480-4
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020221
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Remediation where authselect tool is not present and PAM files are directly
edited
block:
- name: Ensure the desired remember value is updated in the custom profile
ansible.builtin.replace:
dest: /etc/pam.d/system-auth
regexp: (.*pam_pwhistory.so.*remember=)(\S+)(.*)$
replace: \g<1>{{ var_password_pam_remember }}\g<3>
when:
- result_pam_pwhistory_present.found == 1
- name: Ensure the remember parameter is included in the custom profile
ansible.builtin.replace:
dest: /etc/pam.d/system-auth
regexp: (.*pam_pwhistory.so.*)(?! remember=\S+)(.*)$
replace: \g<1> \g<2> remember={{ var_password_pam_remember }}
when:
- result_pam_pwhistory_present.found == 1
- result_pam_pwhistory_remember_present.found == 0
- name: Ensure the desired control value is updated in the custom profile
ansible.builtin.replace:
dest: /etc/pam.d/system-auth
regexp: ^(password\s+)((?:(?:requisite)|(?:required)))(\s+pam_pwhistory\.so\s.*)$
replace: \g<1>{{ var_password_pam_remember_control_flag }}\g<3>
when:
- result_pam_pwhistory_present.found == 1
- name: Ensure the desired configuration is present in the custom profile
ansible.builtin.lineinfile:
dest: /etc/pam.d/system-auth
insertafter: ^password.*requisite.*pam_pwquality.so.*
line: password {{ var_password_pam_remember_control_flag }} pam_pwhistory.so
remember={{ var_password_pam_remember }} use_authtok
when:
- result_pam_pwhistory_present.found == 0
when:
- '"pam" in ansible_facts.packages'
- not result_authselect_present.stat.exists
tags:
- CCE-83480-4
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020221
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_pwhistory_remember_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_remember='5'
var_password_pam_remember_control_flag='required'
# control required is for rhel8, while requisite is for other distros
CONTROL=${var_password_pam_remember_control_flag}
if [ -f /usr/bin/authselect ]; then
if authselect check; then
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# Standard profiles delivered with authselect should not be modified.
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
# Ensure a backup before changing the profile
authselect apply-changes -b --backup=before-pwhistory-hardening.backup
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
fi
# Include the desired configuration in the custom profile
CUSTOM_SYSTEM_AUTH="/etc/authselect/$CURRENT_PROFILE/system-auth"
if grep -q "^password.*pam_pwhistory.so.*" $CUSTOM_SYSTEM_AUTH; then
if ! grep -q "^[^#].*pam_pwhistory.so.*remember=" $CUSTOM_SYSTEM_AUTH; then
sed -i --follow-symlinks "/pam_pwhistory.so/ s/$/ remember=$var_password_pam_remember/" $CUSTOM_SYSTEM_AUTH
else
sed -r -i --follow-symlinks "s/(.*pam_pwhistory.so.*)(remember=[[:digit:]]+)\s(.*)/\1remember=$var_password_pam_remember \3/g" $CUSTOM_SYSTEM_AUTH
fi
# Ensure correct control is being used per os requirement
if ! grep -q "^password.*$CONTROL.*pam_pwhistory.so.*" $CUSTOM_SYSTEM_AUTH; then
# Replace incorrect value
sed -r -i --follow-symlinks "s/(^password.*)(required|requisite)(.*pam_pwhistory\.so.*)$/\1$CONTROL\3/" $CUSTOM_SYSTEM_AUTH
fi
else
sed -i --follow-symlinks "/^password.*requisite.*pam_pwquality.so/a password $CONTROL pam_pwhistory.so remember=$var_password_pam_remember use_authtok" $CUSTOM_SYSTEM_AUTH
fi
authselect apply-changes -b --backup=after-pwhistory-hardening.backup
else
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because the authselect profile is not intact.
It is not recommended to manually edit the PAM files when authselect is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
false
fi
else
pamFile="/etc/pam.d/system-auth"
# is 'password required|requisite pam_pwhistory.so' here?
if grep -q "^password.*pam_pwhistory.so.*" $pamFile; then
# is the remember option set?
option=$(sed -rn 's/^(.*pam_pwhistory\.so.*)(remember=[0-9]+)(.*)$/\2/p' $pamFile)
if [[ -z $option ]]; then
# option is not set, append to module
sed -i --follow-symlinks "/pam_pwhistory.so/ s/$/ remember=$var_password_pam_remember/" $pamFile
else
# option is set, replace value
sed -r -i --follow-symlinks "s/^(.*pam_pwhistory\.so.*)(remember=[0-9]+)(.*)$/\1remember=$var_password_pam_remember\3/" $pamFile
fi
# ensure correct control is being used per os requirement
if ! grep -q "^password.*$CONTROL.*pam_pwhistory.so.*" $pamFile; then
#replace incorrect value
sed -r -i --follow-symlinks "s/(^password.*)(required|requisite)(.*pam_pwhistory\.so.*)$/\1$CONTROL\3/" $pamFile
fi
else
# no 'password required|requisite pam_pwhistory.so', add it
sed -i --follow-symlinks "/^password.*pam_unix.so.*/i password $CONTROL pam_pwhistory.so use_authtok remember=$var_password_pam_remember" $pamFile
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Password Quality Requirements
[ref]groupThe default pam_pwquality PAM module provides strength
checking for passwords. It performs a number of checks, such as
making sure passwords are not similar to dictionary words, are of
at least a certain length, are not the previous password reversed,
and are not simply a change of case from the previous password. It
can also require passwords to be in certain character classes. The
pam_pwquality module is the preferred way of configuring
password requirements.
The man pages pam_pwquality(8)
provide information on the capabilities and configuration of
each. |
contains 3 rules |
Set Password Quality Requirements with pam_pwquality
[ref]groupThe pam_pwquality PAM module can be configured to meet
requirements for a variety of policies.
For example, to configure pam_pwquality to require at least one uppercase
character, lowercase character, digit, and other (special)
character, make sure that pam_pwquality exists in /etc/pam.d/system-auth :
password requisite pam_pwquality.so try_first_pass local_users_only retry=3 authtok_type=
If no such line exists, add one as the first line of the password section in /etc/pam.d/system-auth .
Next, modify the settings in /etc/security/pwquality.conf to match the following:
difok = 4
minlen = 14
dcredit = -1
ucredit = -1
lcredit = -1
ocredit = -1
maxrepeat = 3
The arguments can be modified to ensure compliance with
your organization's security policy. Discussion of each parameter follows. |
contains 3 rules |
Ensure PAM Enforces Password Requirements - Minimum Different Categories
[ref]ruleThe pam_pwquality module's minclass parameter controls
requirements for usage of different character classes, or types, of character
that must exist in a password before it is considered valid. For example,
setting this value to three (3) requires that any password must have characters
from at least three different categories in order to be approved. The default
value is zero (0), meaning there are no required classes. There are four
categories available:
* Upper-case characters
* Lower-case characters
* Digits
* Special characters (for example, punctuation)
Modify the minclass setting in /etc/security/pwquality.conf entry
to require 4
differing categories of characters when changing passwords.Rationale:Use of a complex password helps to increase the time and resources required to compromise the password.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts
at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The
more complex the password, the greater the number of possible combinations that need to be tested before
the password is compromised.
Requiring a minimum number of character categories makes password guessing attacks more difficult
by ensuring a larger search space. Identifiers:
CCE-82046-4 References:
1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000195, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000072-GPOS-00040, RHEL-08-020160, 5.4.1, SV-230362r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-82046-4
- DISA-STIG-RHEL-08-020160
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(4)
- NIST-800-53-IA-5(c)
- accounts_password_pam_minclass
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_password_pam_minclass # promote to variable
set_fact:
var_password_pam_minclass: !!str 4
tags:
- always
- name: Ensure PAM variable minclass is set accordingly
lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*minclass
line: minclass = {{ var_password_pam_minclass }}
when: '"pam" in ansible_facts.packages'
tags:
- CCE-82046-4
- DISA-STIG-RHEL-08-020160
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(4)
- NIST-800-53-IA-5(c)
- accounts_password_pam_minclass
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_minclass='4'
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/security/pwquality.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^minclass")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_minclass"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^minclass\\>" "/etc/security/pwquality.conf"; then
"${sed_command[@]}" "s/^minclass\\>.*/$formatted_output/gi" "/etc/security/pwquality.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-82046-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/security/pwquality.conf" >> "/etc/security/pwquality.conf"
printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure PAM Enforces Password Requirements - Minimum Length
[ref]ruleThe pam_pwquality module's minlen parameter controls requirements for
minimum characters required in a password. Add minlen=14
after pam_pwquality to set minimum password length requirements. Rationale:The shorter the password, the lower the number of possible combinations
that need to be tested before the password is compromised.
Password complexity, or strength, is a measure of the effectiveness of a
password in resisting attempts at guessing and brute-force attacks.
Password length is one factor of several that helps to determine strength
and how long it takes to crack a password. Use of more characters in a password
helps to exponentially increase the time and/or resources required to
compromose the password. Identifiers:
CCE-80656-2 References:
BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000205, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, FMT_MOF_EXT.1, Req-8.2.3, SRG-OS-000078-GPOS-00046, SRG-OS-000072-VMM-000390, SRG-OS-000078-VMM-000450, RHEL-08-020230, 5.4.1, SV-230369r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80656-2
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020230
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(4)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_password_pam_minlen # promote to variable
set_fact:
var_password_pam_minlen: !!str 14
tags:
- always
- name: Ensure PAM variable minlen is set accordingly
lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*minlen
line: minlen = {{ var_password_pam_minlen }}
when: '"pam" in ansible_facts.packages'
tags:
- CCE-80656-2
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020230
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(4)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_minlen='14'
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/security/pwquality.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^minlen")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_minlen"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^minlen\\>" "/etc/security/pwquality.conf"; then
"${sed_command[@]}" "s/^minlen\\>.*/$formatted_output/gi" "/etc/security/pwquality.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80656-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/security/pwquality.conf" >> "/etc/security/pwquality.conf"
printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted Per-Session
[ref]ruleTo configure the number of retry prompts that are permitted per-session:
Edit the /etc/security/pwquality.conf to include
retry=3 , or a lower value if site
policy is more restrictive. The DoD requirement is a maximum of 3 prompts
per session. Rationale:Setting the password retry prompts that are permitted on a per-session basis to a low value
requires some software, such as SSH, to re-connect. This can slow down and
draw additional attention to some types of password-guessing attacks. Note that this
is different from account lockout, which is provided by the pam_faillock module. Identifiers:
CCE-80664-6 References:
1, 11, 12, 15, 16, 3, 5, 9, 5.5.3, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000192, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, PR.IP-1, FMT_MOF_EXT.1, SRG-OS-000069-GPOS-00037, RHEL-08-020104, 5.4.1, SV-251716r809372_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80664-6
- CJIS-5.5.3
- DISA-STIG-RHEL-08-020104
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(4)
- accounts_password_pam_retry
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_retry # promote to variable
set_fact:
var_password_pam_retry: !!str 3
tags:
- always
- name: Ensure PAM variable retry is set accordingly
ansible.builtin.lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*retry
line: retry = {{ var_password_pam_retry }}
when: '"pam" in ansible_facts.packages'
tags:
- CCE-80664-6
- CJIS-5.5.3
- DISA-STIG-RHEL-08-020104
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(4)
- accounts_password_pam_retry
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_retry='3'
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/security/pwquality.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^retry")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_retry"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^retry\\>" "/etc/security/pwquality.conf"; then
"${sed_command[@]}" "s/^retry\\>.*/$formatted_output/gi" "/etc/security/pwquality.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80664-6"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/security/pwquality.conf" >> "/etc/security/pwquality.conf"
printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Password Hashing Algorithm
[ref]groupThe system's default algorithm for storing password hashes in
/etc/shadow is SHA-512. This can be configured in several
locations. |
contains 1 rule |
Set PAM's Password Hashing Algorithm
[ref]ruleThe PAM system service can be configured to only store encrypted
representations of passwords. In "/etc/pam.d/password-auth", the
password section of the file controls which PAM modules execute
during a password change. Set the pam_unix.so module in the
password section to include the argument sha512 , as shown
below:
password sufficient pam_unix.so sha512 other arguments...
This will help ensure when local users change their passwords, hashes for
the new passwords will be generated using the SHA-512 algorithm. This is
the default.Rationale:Passwords need to be protected at all times, and encryption is the standard
method for protecting passwords. If passwords are not encrypted, they can
be plainly read (i.e., clear text) and easily compromised. Passwords that
are encrypted with a weak algorithm are no more protected than if they are
kepy in plain text.
This setting ensures user and group account administration utilities are
configured to store only encrypted representations of passwords.
Additionally, the crypt_style configuration option ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. Identifiers:
CCE-80893-1 References:
BP28(R32), 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, SRG-OS-000073-GPOS-00041, SRG-OS-000480-VMM-002000, RHEL-08-010159, 5.4.4, SV-244524r809331_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
AUTH_FILES[0]="/etc/pam.d/system-auth"
for pamFile in "${AUTH_FILES[@]}"
do
if ! grep -q "^password.*sufficient.*pam_unix.so.*sha512" $pamFile; then
sed -i --follow-symlinks "/^password.*sufficient.*pam_unix.so/ s/$/ sha512/" $pamFile
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Protect Physical Console Access
[ref]groupIt is impossible to fully protect a system from an
attacker with physical access, so securing the space in which the
system is located should be considered a necessary step. However,
there are some steps which, if taken, make it more difficult for an
attacker to quickly or undetectably modify a system from its
console. |
contains 2 rules |
Require Authentication for Emergency Systemd Target
[ref]ruleEmergency mode is intended as a system recovery
method, providing a single user root access to the system
during a failed boot sequence.
By default, Emergency mode is protected by requiring a password and is set
in /usr/lib/systemd/system/emergency.service . Rationale:This prevents attackers with physical access from trivially bypassing security
on the machine and gaining root access. Such accesses are further prevented
by configuring the bootloader password. Identifiers:
CCE-82186-8 References:
1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-2, AC-3, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, RHEL-08-010152, 1.5.3, SV-244523r743818_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: require emergency mode password
lineinfile:
create: true
dest: /usr/lib/systemd/system/emergency.service
regexp: ^#?ExecStart=
line: ExecStart=-/usr/lib/systemd/systemd-sulogin-shell emergency
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82186-8
- DISA-STIG-RHEL-08-010152
- NIST-800-171-3.1.1
- NIST-800-171-3.4.5
- NIST-800-53-AC-3
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- require_emergency_target_auth
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
service_file="/usr/lib/systemd/system/emergency.service"
sulogin="/usr/lib/systemd/systemd-sulogin-shell emergency"
if grep "^ExecStart=.*" "$service_file" ; then
sed -i "s%^ExecStart=.*%ExecStart=-$sulogin%" "$service_file"
else
echo "ExecStart=-$sulogin" >> "$service_file"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Require Authentication for Single User Mode
[ref]ruleSingle-user mode is intended as a system recovery
method, providing a single user root access to the system by
providing a boot option at startup. By default, no authentication
is performed if single-user mode is selected.
By default, single-user mode is protected by requiring a password and is set
in /usr/lib/systemd/system/rescue.service . Rationale:This prevents attackers with physical access from trivially bypassing security
on the machine and gaining root access. Such accesses are further prevented
by configuring the bootloader password. Identifiers:
CCE-80855-0 References:
1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, AC-3, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, RHEL-08-010151, 1.5.3, SV-230236r743928_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: require single user mode password
lineinfile:
create: true
dest: /usr/lib/systemd/system/rescue.service
regexp: ^#?ExecStart=
line: ExecStart=-/usr/lib/systemd/systemd-sulogin-shell rescue
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80855-0
- DISA-STIG-RHEL-08-010151
- NIST-800-171-3.1.1
- NIST-800-171-3.4.5
- NIST-800-53-AC-3
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- require_singleuser_auth
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
service_file="/usr/lib/systemd/system/rescue.service"
sulogin="/usr/lib/systemd/systemd-sulogin-shell rescue"
if grep "^ExecStart=.*" "$service_file" ; then
sed -i "s%^ExecStart=.*%ExecStart=-$sulogin%" "$service_file"
else
echo "ExecStart=-$sulogin" >> "$service_file"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Protect Accounts by Restricting Password-Based Login
[ref]groupConventionally, Unix shell accounts are accessed by
providing a username and password to a login program, which tests
these values for correctness using the /etc/passwd and
/etc/shadow files. Password-based login is vulnerable to
guessing of weak passwords, and to sniffing and man-in-the-middle
attacks against passwords entered over a network or at an insecure
console. Therefore, mechanisms for accessing accounts by entering
usernames and passwords should be restricted to those which are
operationally necessary. |
contains 18 rules |
Set Account Expiration Parameters
[ref]groupAccounts can be configured to be automatically disabled
after a certain time period,
meaning that they will require administrator interaction to become usable again.
Expiration of accounts after inactivity can be set for all accounts by default
and also on a per-account basis, such as for accounts that are known to be temporary.
To configure automatic expiration of an account following
the expiration of its password (that is, after the password has expired and not been changed),
run the following command, substituting NUM_DAYS and USER appropriately:
$ sudo chage -I NUM_DAYS USER
Accounts, such as temporary accounts, can also be configured to expire on an explicitly-set date with the
-E option.
The file /etc/default/useradd controls
default settings for all newly-created accounts created with the system's
normal command line utilities.Warning:
This will only apply to newly created accounts |
contains 2 rules |
Set Account Expiration Following Inactivity
[ref]ruleTo specify the number of days after a password expires (which
signifies inactivity) until an account is permanently disabled, add or correct
the following line in /etc/default/useradd :
INACTIVE=30
If a password is currently on the verge of expiration, then
30
day(s) remain(s) until the account is automatically
disabled. However, if the password will not expire for another 60 days, then 60
days plus 30 day(s) could
elapse until the account would be automatically disabled. See the
useradd man page for more information.Rationale:Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system.
Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials.
Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained. Identifiers:
CCE-80954-1 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.6.2.1.1, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000017, CCI-000795, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, IA-4(e), AC-2(3), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, Req-8.1.4, SRG-OS-000118-GPOS-00060, SRG-OS-000003-VMM-000030, SRG-OS-000118-VMM-000590, RHEL-08-020260, 5.5.1.4, SV-230373r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80954-1
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020260
- NIST-800-171-3.5.6
- NIST-800-53-AC-2(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-4(e)
- PCI-DSS-Req-8.1.4
- account_disable_post_pw_expiration
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_account_disable_post_pw_expiration # promote to variable
set_fact:
var_account_disable_post_pw_expiration: !!str 30
tags:
- always
- name: Set Account Expiration Following Inactivity
lineinfile:
create: true
dest: /etc/default/useradd
regexp: ^INACTIVE
line: INACTIVE={{ var_account_disable_post_pw_expiration }}
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CCE-80954-1
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020260
- NIST-800-171-3.5.6
- NIST-800-53-AC-2(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-4(e)
- PCI-DSS-Req-8.1.4
- account_disable_post_pw_expiration
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_account_disable_post_pw_expiration='30'
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/default/useradd"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^INACTIVE")
# shellcheck disable=SC2059
printf -v formatted_output "%s=%s" "$stripped_key" "$var_account_disable_post_pw_expiration"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^INACTIVE\\>" "/etc/default/useradd"; then
"${sed_command[@]}" "s/^INACTIVE\\>.*/$formatted_output/gi" "/etc/default/useradd"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80954-1"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/default/useradd" >> "/etc/default/useradd"
printf '%s\n' "$formatted_output" >> "/etc/default/useradd"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure All Accounts on the System Have Unique Names
[ref]ruleEnsure accounts on the system have unique names.
To ensure all accounts have unique names, run the following command:
$ sudo getent passwd | awk -F: '{ print $1}' | uniq -d
If a username is returned, change or delete the username.Rationale:Unique usernames allow for accountability on the system. |
Set Password Expiration Parameters
[ref]groupThe file /etc/login.defs controls several
password-related settings. Programs such as passwd ,
su , and
login consult /etc/login.defs to determine
behavior with regard to password aging, expiration warnings,
and length. See the man page login.defs(5) for more information.
Users should be forced to change their passwords, in order to
decrease the utility of compromised passwords. However, the need to
change passwords often should be balanced against the risk that
users will reuse or write down passwords if forced to change them
too often. Forcing password changes every 90-360 days, depending on
the environment, is recommended. Set the appropriate value as
PASS_MAX_DAYS and apply it to existing accounts with the
-M flag.
The PASS_MIN_DAYS (-m ) setting prevents password
changes for 7 days after the first change, to discourage password
cycling. If you use this setting, train users to contact an administrator
for an emergency password change in case a new password becomes
compromised. The PASS_WARN_AGE (-W ) setting gives
users 7 days of warnings at login time that their passwords are about to expire.
For example, for each existing human user USER, expiration parameters
could be adjusted to a 180 day maximum password age, 7 day minimum password
age, and 7 day warning period with the following command:
$ sudo chage -M 180 -m 7 -W 7 USER |
contains 5 rules |
Set Password Maximum Age
[ref]ruleTo specify password maximum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MAX_DAYS 365
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
The profile requirement is 365 .Rationale:Any password, no matter how complex, can eventually be cracked. Therefore, passwords
need to be changed periodically. If the operating system does not limit the lifetime
of passwords and force users to change their passwords, there is the risk that the
operating system passwords could be compromised.
Setting the password maximum age ensures users are required to
periodically change their passwords. Requiring shorter password lifetimes
increases the risk of users writing down the password in a convenient
location subject to physical compromise. Identifiers:
CCE-80647-1 References:
BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000199, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(d), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.4, SRG-OS-000076-GPOS-00044, RHEL-08-020200, 5.5.1.1, SV-230366r646878_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80647-1
- CJIS-5.6.2.1
- DISA-STIG-RHEL-08-020200
- NIST-800-171-3.5.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_maximum_age_login_defs # promote to variable
set_fact:
var_accounts_maximum_age_login_defs: !!str 365
tags:
- always
- name: Set Password Maximum Age
lineinfile:
create: true
dest: /etc/login.defs
regexp: ^#?PASS_MAX_DAYS
line: PASS_MAX_DAYS {{ var_accounts_maximum_age_login_defs }}
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CCE-80647-1
- CJIS-5.6.2.1
- DISA-STIG-RHEL-08-020200
- NIST-800-171-3.5.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_maximum_age_login_defs='365'
grep -q ^PASS_MAX_DAYS /etc/login.defs && \
sed -i "s/PASS_MAX_DAYS.*/PASS_MAX_DAYS $var_accounts_maximum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_MAX_DAYS $var_accounts_maximum_age_login_defs" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Password Minimum Age
[ref]ruleTo specify password minimum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MIN_DAYS 7
A value of 1 day is considered sufficient for many
environments. The DoD requirement is 1.
The profile requirement is 7 .Rationale:Enforcing a minimum password lifetime helps to prevent repeated password
changes to defeat the password reuse or history enforcement requirement. If
users are allowed to immediately and continually change their password,
then the password could be repeatedly changed in a short period of time to
defeat the organization's policy regarding password reuse.
Setting the minimum password age protects against users cycling back to a
favorite password after satisfying the password reuse requirement. Identifiers:
CCE-80648-9 References:
1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, CCI-000198, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(d), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000075-GPOS-00043, RHEL-08-020190, 5.5.1.2, SV-230365r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80648-9
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020190
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_minimum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_minimum_age_login_defs # promote to variable
set_fact:
var_accounts_minimum_age_login_defs: !!str 7
tags:
- always
- name: Set Password Minimum Age
lineinfile:
create: true
dest: /etc/login.defs
regexp: ^#?PASS_MIN_DAYS
line: PASS_MIN_DAYS {{ var_accounts_minimum_age_login_defs }}
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CCE-80648-9
- CJIS-5.6.2.1.1
- DISA-STIG-RHEL-08-020190
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_minimum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_minimum_age_login_defs='7'
grep -q ^PASS_MIN_DAYS /etc/login.defs && \
sed -i "s/PASS_MIN_DAYS.*/PASS_MIN_DAYS $var_accounts_minimum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_MIN_DAYS $var_accounts_minimum_age_login_defs" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Existing Passwords Maximum Age
[ref]ruleConfigure non-compliant accounts to enforce a 365-day maximum password lifetime
restriction by running the following command:
$ sudo chage -M 365 USER Rationale:Any password, no matter how complex, can eventually be cracked. Therefore,
passwords need to be changed periodically. If the operating system does
not limit the lifetime of passwords and force users to change their
passwords, there is the risk that the operating system passwords could be
compromised. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
var_accounts_maximum_age_login_defs='365'
while IFS= read -r i; do
passwd -x $var_accounts_maximum_age_login_defs $i
done < <(awk -v var="$var_accounts_maximum_age_login_defs" -F: '$5 > var || $5 == "" {print $1}' /etc/shadow)
|
Set Existing Passwords Minimum Age
[ref]ruleConfigure non-compliant accounts to enforce a 24 hours/1 day minimum password
lifetime by running the following command:
$ sudo chage -m 1 USER Rationale:Enforcing a minimum password lifetime helps to prevent repeated password
changes to defeat the password reuse or history enforcement requirement. If
users are allowed to immediately and continually change their password, the
password could be repeatedly changed in a short period of time to defeat the
organization's policy regarding password reuse. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
var_accounts_minimum_age_login_defs='7'
while IFS= read -r i; do
passwd -n $var_accounts_minimum_age_login_defs $i
done < <(awk -v var="$var_accounts_minimum_age_login_defs" -F: '$4 < var || $4 == "" {print $1}' /etc/shadow)
|
Set Password Warning Age
[ref]ruleTo specify how many days prior to password
expiration that a warning will be issued to users,
edit the file /etc/login.defs and add or correct
the following line:
PASS_WARN_AGE 7
The DoD requirement is 7.
The profile requirement is 7 .Rationale:Setting the password warning age enables users to
make the change at a practical time. Identifiers:
CCE-80671-1 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, 0418, 1055, 1402, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(f), IA-5(1)(d), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, 5.5.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80671-1
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_password_warn_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_password_warn_age_login_defs # promote to variable
set_fact:
var_accounts_password_warn_age_login_defs: !!str 7
tags:
- always
- name: Set Password Warning Age
lineinfile:
dest: /etc/login.defs
regexp: ^PASS_WARN_AGE *[0-9]*
state: present
line: PASS_WARN_AGE {{ var_accounts_password_warn_age_login_defs }}
create: true
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CCE-80671-1
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_password_warn_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_password_warn_age_login_defs='7'
grep -q ^PASS_WARN_AGE /etc/login.defs && \
sed -i "s/PASS_WARN_AGE.*/PASS_WARN_AGE\t$var_accounts_password_warn_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]
then
echo -e "PASS_WARN_AGE\t$var_accounts_password_warn_age_login_defs" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Proper Storage and Existence of Password
Hashes
[ref]groupBy default, password hashes for local accounts are stored
in the second field (colon-separated) in
/etc/shadow . This file should be readable only by
processes running with root credentials, preventing users from
casually accessing others' password hashes and attempting
to crack them.
However, it remains possible to misconfigure the system
and store password hashes
in world-readable files such as /etc/passwd , or
to even store passwords themselves in plaintext on the system.
Using system-provided tools for password change/creation
should allow administrators to avoid such misconfiguration. |
contains 4 rules |
Ensure there are no legacy + NIS entries in /etc/group
[ref]ruleThe + character in /etc/group file marks a place where
entries from a network information service (NIS) should be directly inserted. Rationale:Using this method to include entries into /etc/group is considered legacy
and should be avoided. These entries may provide a way for an attacker
to gain access to the system. Identifiers:
CCE-83389-7 References:
6.2.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Backup the old /etc/group file
copy:
src: /etc/group
dest: /etc/group-
remote_src: true
tags:
- CCE-83389-7
- low_complexity
- medium_disruption
- medium_severity
- no_legacy_plus_entries_etc_group
- no_reboot_needed
- restrict_strategy
- name: Remove lines starting with + from /etc/group
lineinfile:
regexp: ^\+.*$
state: absent
path: /etc/group
tags:
- CCE-83389-7
- low_complexity
- medium_disruption
- medium_severity
- no_legacy_plus_entries_etc_group
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
if grep -q '^\+' /etc/group; then
# backup old file to /etc/group-
cp /etc/group /etc/group-
sed -i '/^\+.*$/d' /etc/group
fi
|
Ensure there are no legacy + NIS entries in /etc/passwd
[ref]ruleThe + character in /etc/passwd file marks a place where
entries from a network information service (NIS) should be directly inserted. Rationale:Using this method to include entries into /etc/passwd is considered legacy
and should be avoided. These entries may provide a way for an attacker
to gain access to the system. Identifiers:
CCE-82890-5 References:
6.2.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Backup the old /etc/passwd file
copy:
src: /etc/passwd
dest: /etc/passwd-
remote_src: true
tags:
- CCE-82890-5
- low_complexity
- medium_disruption
- medium_severity
- no_legacy_plus_entries_etc_passwd
- no_reboot_needed
- restrict_strategy
- name: Remove lines starting with + from /etc/passwd
lineinfile:
regexp: ^\+.*$
state: absent
path: /etc/passwd
tags:
- CCE-82890-5
- low_complexity
- medium_disruption
- medium_severity
- no_legacy_plus_entries_etc_passwd
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
if grep -q '^\+' /etc/passwd; then
# backup old file to /etc/passwd-
cp /etc/passwd /etc/passwd-
sed -i '/^\+.*$/d' /etc/passwd
fi
|
Ensure there are no legacy + NIS entries in /etc/shadow
[ref]ruleThe + character in /etc/shadow file marks a place where
entries from a network information service (NIS) should be directly inserted. Rationale:Using this method to include entries into /etc/shadow is considered legacy
and should be avoided. These entries may provide a way for an attacker
to gain access to the system. Identifiers:
CCE-84290-6 References:
6.2.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Backup the old /etc/shadow file
copy:
src: /etc/shadow
dest: /etc/shadow-
remote_src: true
tags:
- CCE-84290-6
- low_complexity
- medium_disruption
- medium_severity
- no_legacy_plus_entries_etc_shadow
- no_reboot_needed
- restrict_strategy
- name: Remove lines starting with + from /etc/shadow
lineinfile:
regexp: ^\+.*$
state: absent
path: /etc/shadow
tags:
- CCE-84290-6
- low_complexity
- medium_disruption
- medium_severity
- no_legacy_plus_entries_etc_shadow
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
if grep -q '^\+' /etc/shadow; then
# backup old file to /etc/shadow-
cp /etc/shadow /etc/shadow-
sed -i '/^\+.*$/d' /etc/shadow
fi
|
Verify No netrc Files Exist
[ref]ruleThe .netrc files contain login information
used to auto-login into FTP servers and reside in the user's home
directory. These files may contain unencrypted passwords to
remote FTP servers making them susceptible to access by unauthorized
users and should not be used. Any .netrc files should be removed. Rationale:Unencrypted passwords for remote FTP servers may be stored in .netrc
files. Identifiers:
CCE-83444-0 References:
1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, CCI-000196, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R1.3, CIP-003-8 R3, CIP-003-8 R3.1, CIP-003-8 R3.2, CIP-003-8 R3.3, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-5(h), IA-5(1)(c), CM-6(a), IA-5(7), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, 6.2.11 |
Restrict Root Logins
[ref]groupDirect root logins should be allowed only for emergency use.
In normal situations, the administrator should access the system
via a unique unprivileged account, and then use su or sudo to execute
privileged commands. Discouraging administrators from accessing the
root account directly ensures an audit trail in organizations with
multiple administrators. Locking down the channels through which
root can connect directly also reduces opportunities for
password-guessing against the root account. The login program
uses the file /etc/securetty to determine which interfaces
should allow root logins.
The virtual devices /dev/console
and /dev/tty* represent the system consoles (accessible via
the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default
installation). The default securetty file also contains /dev/vc/* .
These are likely to be deprecated in most environments, but may be retained
for compatibility. Root should also be prohibited from connecting
via network protocols. Other sections of this document
include guidance describing how to prevent root from logging in via SSH. |
contains 4 rules |
Verify Only Root Has UID 0
[ref]ruleIf any account other than root has a UID of 0, this misconfiguration should
be investigated and the accounts other than root should be removed or have
their UID changed.
If the account is associated with system commands or applications the UID
should be changed to one greater than "0" but less than "1000."
Otherwise assign a UID greater than "1000" that has not already been
assigned. Rationale:An account has root authority if it has a UID of 0. Multiple accounts
with a UID of 0 afford more opportunity for potential intruders to
guess a password for a privileged account. Proper configuration of
sudo is recommended to afford multiple system administrators
access to root privileges in an accountable manner. Identifiers:
CCE-80649-7 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, AC-6(5), IA-4(b), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, SRG-OS-000480-GPOS-00227, RHEL-08-040200, 6.2.6, SV-230534r627750_rule Remediation Shell script: (show)
awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs --no-run-if-empty --max-lines=1 passwd -l
|
Verify Root Has A Primary GID 0
[ref]ruleThe root user should have a primary group of 0. Rationale:To help ensure that root-owned files are not inadvertently exposed to other users. Identifiers:
CCE-86297-9 References:
5.5.4 |
Ensure that System Accounts Do Not Run a Shell Upon Login
[ref]ruleSome accounts are not associated with a human user of the system, and exist to
perform some administrative function. Should an attacker be able to log into
these accounts, they should not be granted access to a shell.
The login shell for each local account is stored in the last field of each line
in /etc/passwd . System accounts are those user accounts with a user ID
less than UID_MIN, where value of UID_MIN directive is set in
/etc/login.defs configuration file. In the default configuration UID_MIN is set
to 1000, thus system accounts are those user accounts with a user ID less than
1000. The user ID is stored in the third field. If any system account
SYSACCT (other than root) has a login shell, disable it with the
command: $ sudo usermod -s /sbin/nologin SYSACCT Warning:
Do not perform the steps in this section on the root account. Doing so might
cause the system to become inaccessible. Rationale:Ensuring shells are not given to system accounts upon login makes it more
difficult for attackers to make use of system accounts. Identifiers:
CCE-80843-6 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS06.03, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, 1491, A.12.4.1, A.12.4.3, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-6, CM-6(a), CM-6(b), CM-6.1(iv), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, SRG-OS-000480-GPOS-00227, 5.5.2 |
Enforce usage of pam_wheel for su authentication
[ref]ruleTo ensure that only users who are members of the wheel group can
run commands with altered privileges through the su command, make
sure that the following line exists in the file /etc/pam.d/su :
auth required pam_wheel.so use_uid Rationale:The su program allows to run commands with a substitute user and
group ID. It is commonly used to run commands as the root user. Limiting
access to such command is considered a good security practice. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: restrict usage of su command only to members of wheel group
replace:
path: /etc/pam.d/su
regexp: ^[\s]*#[\s]*auth[\s]+required[\s]+pam_wheel\.so[\s]+use_uid$
replace: auth required pam_wheel.so use_uid
tags:
- CCE-83318-6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- use_pam_wheel_for_su
Remediation Shell script: (show)
# uncomment the option if commented
sed '/^[[:space:]]*#[[:space:]]*auth[[:space:]]\+required[[:space:]]\+pam_wheel\.so[[:space:]]\+use_uid$/s/^[[:space:]]*#//' -i /etc/pam.d/su
|
Ensure All Accounts on the System Have Unique User IDs
[ref]ruleChange user IDs (UIDs), or delete accounts, so each has a unique name. Warning:
Automatic remediation of this control is not available due to unique requirements of each
system. Rationale:To assure accountability and prevent unauthenticated access, interactive users must be identified and authenticated to prevent potential misuse and compromise of the system. |
Ensure All Groups on the System Have Unique Group ID
[ref]ruleChange the group name or delete groups, so each has a unique id. Warning:
Automatic remediation of this control is not available due to the unique requirements of each system. Rationale:To assure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system. |
Ensure All Groups on the System Have Unique Group Names
[ref]ruleChange the group name or delete groups, so each has a unique name. Warning:
Automatic remediation of this control is not available due to the unique requirements of each system. Rationale:To assure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system. Identifiers:
CCE-86328-2 References:
6.2.18 |
Secure Session Configuration Files for Login Accounts
[ref]groupWhen a user logs into a Unix account, the system
configures the user's session by reading a number of files. Many of
these files are located in the user's home directory, and may have
weak permissions as a result of user error or misconfiguration. If
an attacker can modify or even read certain types of account
configuration information, they can often gain full access to the
affected user's account. Therefore, it is important to test and
correct configuration file permissions for interactive accounts,
particularly those of privileged users such as root or system
administrators. |
contains 10 rules |
Ensure that No Dangerous Directories Exist in Root's Path
[ref]groupThe active path of the root account can be obtained by
starting a new root shell and running:
# echo $PATH
This will produce a colon-separated list of
directories in the path.
Certain path elements could be considered dangerous, as they could lead
to root executing unknown or
untrusted programs, which could contain malicious
code.
Since root may sometimes work inside
untrusted directories, the . character, which represents the
current directory, should never be in the root path, nor should any
directory which can be written to by an unprivileged or
semi-privileged (system) user.
It is a good practice for administrators to always execute
privileged commands by typing the full path to the
command. |
contains 2 rules |
Ensure that Root's Path Does Not Include World or Group-Writable Directories
[ref]ruleFor each element in root's path, run:
# ls -ld DIR
and ensure that write permissions are disabled for group and
other.Rationale:Such entries increase the risk that root could
execute code provided by unprivileged users,
and potentially malicious code. Identifiers:
CCE-80672-9 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(a), CM-6(a), PR.IP-1, 6.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Print error message if user is not root
fail:
msg: Root account required to read root $PATH
when: ansible_env.USER != "root"
ignore_errors: true
tags:
- CCE-80672-9
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(a)
- accounts_root_path_dirs_no_write
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Get root paths which are not symbolic links
stat:
path: '{{ item }}'
changed_when: false
failed_when: false
register: root_paths
with_items: '{{ ansible_env.PATH.split('':'') }}'
when: ansible_env.USER == "root"
tags:
- CCE-80672-9
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(a)
- accounts_root_path_dirs_no_write
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Disable writability to root directories
file:
path: '{{ item.item }}'
mode: g-w,o-w
with_items: '{{ root_paths.results }}'
when:
- root_paths.results is defined
- item.stat.exists
- not item.stat.islnk
tags:
- CCE-80672-9
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(a)
- accounts_root_path_dirs_no_write
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure that Root's Path Does Not Include Relative Paths or Null Directories
[ref]ruleEnsure that none of the directories in root's path is equal to a single
. character, or
that it contains any instances that lead to relative path traversal, such as
.. or beginning a path without the slash (/ ) character.
Also ensure that there are no "empty" elements in the path, such as in these examples:
PATH=:/bin
PATH=/bin:
PATH=/bin::/sbin
These empty elements have the same effect as a single . character.Rationale:Including these entries increases the risk that root could
execute code from an untrusted location. Identifiers:
CCE-85914-0 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(a), CM-6(a), PR.IP-1, 6.2.3 |
Ensure that Users Have Sensible Umask Values
[ref]groupThe umask setting controls the default permissions
for the creation of new files.
With a default umask setting of 077, files and directories
created by users will not be readable by any other user on the
system. Users who wish to make specific files group- or
world-readable can accomplish this by using the chmod command.
Additionally, users can make all their files readable to their
group by default by setting a umask of 027 in their shell
configuration files. If default per-user groups exist (that is, if
every user has a default group whose name is the same as that
user's username and whose only member is the user), then it may
even be safe for users to select a umask of 007, making it very
easy to intentionally share files with groups of which the user is
a member.
|
contains 3 rules |
Ensure the Default Bash Umask is Set Correctly
[ref]ruleTo ensure the default umask for users of the Bash shell is set properly,
add or correct the umask setting in /etc/bashrc to read
as follows:
umask 027 Rationale:The umask value influences the permissions assigned to files when they are created.
A misconfigured umask value could result in files with excessive permissions that can be read or
written to by unauthorized users. Identifiers:
CCE-81036-6 References:
BP28(R35), 18, APO13.01, BAI03.01, BAI03.02, BAI03.03, CCI-000366, 4.3.4.3.3, A.14.1.1, A.14.2.1, A.14.2.5, A.6.1.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6(1), CM-6(a), PR.IP-2, SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227, RHEL-08-020353, 5.5.4, SV-230385r792902_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_accounts_user_umask # promote to variable
set_fact:
var_accounts_user_umask: !!str 027
tags:
- always
- name: Replace user umask in /etc/bashrc
replace:
path: /etc/bashrc
regexp: umask.*
replace: umask {{ var_accounts_user_umask }}
register: umask_replace
tags:
- CCE-81036-6
- DISA-STIG-RHEL-08-020353
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_bashrc
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Append user umask in /etc/bashrc
lineinfile:
create: true
path: /etc/bashrc
line: umask {{ var_accounts_user_umask }}
when: umask_replace is not changed
tags:
- CCE-81036-6
- DISA-STIG-RHEL-08-020353
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_bashrc
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
var_accounts_user_umask='027'
grep -q umask /etc/bashrc && \
sed -i "s/umask.*/umask $var_accounts_user_umask/g" /etc/bashrc
if ! [ $? -eq 0 ]; then
echo "umask $var_accounts_user_umask" >> /etc/bashrc
fi
|
Ensure the Default Umask is Set Correctly in login.defs
[ref]ruleTo ensure the default umask controlled by /etc/login.defs is set properly,
add or correct the UMASK setting in /etc/login.defs to read as follows:
UMASK 027 Rationale:The umask value influences the permissions assigned to files when they are created.
A misconfigured umask value could result in files with excessive permissions that can be read and
written to by unauthorized users. Identifiers:
CCE-82888-9 References:
BP28(R35), 11, 18, 3, 9, APO13.01, BAI03.01, BAI03.02, BAI03.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.1.1, A.14.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.5, A.6.1.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6(1), CM-6(a), PR.IP-1, PR.IP-2, SRG-OS-000480-GPOS-00228, RHEL-08-020351, 5.5.5, SV-230383r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-82888-9
- DISA-STIG-RHEL-08-020351
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_user_umask # promote to variable
set_fact:
var_accounts_user_umask: !!str 027
tags:
- always
- name: Ensure the Default UMASK is Set Correctly
replace:
path: /etc/login.defs
regexp: ^UMASK
replace: UMASK {{ var_accounts_user_umask }}
register: umask_replace
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CCE-82888-9
- DISA-STIG-RHEL-08-020351
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure the Default UMASK is Appended Correctly
lineinfile:
create: true
path: /etc/login.defs
line: UMASK {{ var_accounts_user_umask }}
when:
- '"shadow-utils" in ansible_facts.packages'
- umask_replace is not changed
tags:
- CCE-82888-9
- DISA-STIG-RHEL-08-020351
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_user_umask='027'
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/login.defs"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^UMASK")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_user_umask"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^UMASK\\>" "/etc/login.defs"; then
"${sed_command[@]}" "s/^UMASK\\>.*/$formatted_output/gi" "/etc/login.defs"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-82888-9"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/login.defs" >> "/etc/login.defs"
printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure the Default Umask is Set Correctly in /etc/profile
[ref]ruleTo ensure the default umask controlled by /etc/profile is set properly,
add or correct the umask setting in /etc/profile to read as follows:
umask 027 Rationale:The umask value influences the permissions assigned to files when they are created.
A misconfigured umask value could result in files with excessive permissions that can be read or
written to by unauthorized users. Identifiers:
CCE-81035-8 References:
BP28(R35), 18, APO13.01, BAI03.01, BAI03.02, BAI03.03, CCI-000366, 4.3.4.3.3, A.14.1.1, A.14.2.1, A.14.2.5, A.6.1.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6(1), CM-6(a), PR.IP-2, SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227, RHEL-08-020353, 5.5.4, SV-230385r792902_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_accounts_user_umask # promote to variable
set_fact:
var_accounts_user_umask: !!str 027
tags:
- always
- name: Replace user umask in /etc/profile
replace:
path: /etc/profile
regexp: ^[^#]*umask
replace: umask {{ var_accounts_user_umask }}
register: umask_replace
tags:
- CCE-81035-8
- DISA-STIG-RHEL-08-020353
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_profile
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Append user umask in /etc/profile
lineinfile:
create: true
path: /etc/profile
line: umask {{ var_accounts_user_umask }}
when: umask_replace is not changed
tags:
- CCE-81035-8
- DISA-STIG-RHEL-08-020353
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_profile
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
var_accounts_user_umask='027'
grep -qE '^[^#]*umask' /etc/profile && \
sed -i "s/umask.*/umask $var_accounts_user_umask/g" /etc/profile
if ! [ $? -eq 0 ]; then
echo "umask $var_accounts_user_umask" >> /etc/profile
fi
|
Set Interactive Session Timeout
[ref]ruleSetting the TMOUT option in /etc/profile ensures that
all user sessions will terminate based on inactivity. The TMOUT
setting in a file loaded by /etc/profile , e.g.
/etc/profile.d/tmout.sh should read as follows:
TMOUT=900 Rationale:Terminating an idle session within a short time period reduces
the window of opportunity for unauthorized personnel to take control of a
management session enabled on the console or console port that has been
left unattended. Identifiers:
CCE-80673-7 References:
BP28(R29), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.11, CCI-000057, CCI-001133, CCI-002361, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-12, SC-10, AC-2(5), CM-6(a), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000163-GPOS-00072, SRG-OS-000029-GPOS-00010, SRG-OS-000163-VMM-000700, SRG-OS-000279-VMM-001010, 5.5.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_accounts_tmout # promote to variable
set_fact:
var_accounts_tmout: !!str 900
tags:
- always
- name: Set Interactive Session Timeout
block:
- name: Check for duplicate values
lineinfile:
path: /etc/profile.d/tmout.sh
create: false
regexp: ^\s*TMOUT=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/profile.d/tmout.sh
lineinfile:
path: /etc/profile.d/tmout.sh
create: false
regexp: ^\s*TMOUT=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/profile.d/tmout.sh
lineinfile:
path: /etc/profile.d/tmout.sh
create: true
regexp: ^\s*TMOUT=
line: TMOUT={{ var_accounts_tmout }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80673-7
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_accounts_tmout='900'
# if 0, no occurence of tmout found, if 1, occurence found
tmout_found=0
for f in /etc/profile /etc/profile.d/*.sh; do
if grep --silent '^\s*TMOUT' $f; then
sed -i -E "s/^(\s*)TMOUT\s*=\s*(\w|\$)*(.*)$/\1TMOUT=$var_accounts_tmout\3/g" $f
tmout_found=1
fi
done
if [ $tmout_found -eq 0 ]; then
echo -e "\n# Set TMOUT to $var_accounts_tmout per security requirements" >> /etc/profile.d/tmout.sh
echo "TMOUT=$var_accounts_tmout" >> /etc/profile.d/tmout.sh
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
All Interactive Users Home Directories Must Exist
[ref]ruleCreate home directories to all interactive users that currently do not
have a home directory assigned. Use the following commands to create the user
home directory assigned in /etc/passwd :
$ sudo mkdir /home/USER Rationale:If a local interactive user has a home directory defined that does not exist,
the user may be given access to the / directory as the current working directory
upon logon. This could create a Denial of Service because the user would not be
able to access their logon configuration files, and it may give them visibility
to system files they normally would not be able to access. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Get all local users from /etc/passwd
ansible.builtin.getent:
database: passwd
split: ':'
tags:
- CCE-83424-2
- DISA-STIG-RHEL-08-010750
- accounts_user_interactive_home_directory_exists
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Create local_users variable from the getent output
ansible.builtin.set_fact:
local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
tags:
- CCE-83424-2
- DISA-STIG-RHEL-08-010750
- accounts_user_interactive_home_directory_exists
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure interactive users have a home directory exists
ansible.builtin.user:
name: '{{ item.key }}'
create_home: true
loop: '{{ local_users }}'
when:
- item.value[2]|int >= 1000
- item.value[2]|int != 65534
tags:
- CCE-83424-2
- DISA-STIG-RHEL-08-010750
- accounts_user_interactive_home_directory_exists
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
for user in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534) print $1}' /etc/passwd); do
mkhomedir_helper $user 0077;
done
|
All Interactive User Home Directories Must Be Group-Owned By The Primary User
[ref]ruleChange the group owner of interactive users home directory to the
group found in /etc/passwd . To change the group owner of
interactive users home directory, use the following command:
$ sudo chgrp USER_GROUP /home/USER
This rule ensures every home directory related to an interactive user is
group-owned by an interactive user. It also ensures that interactive users
are group-owners of one and only one home directory.Warning:
Due to OVAL limitation, this rule can report a false negative in a
specific situation where two interactive users swap the group-ownership
of their respective home directories. Rationale:If the Group Identifier (GID) of a local interactive users home directory is
not the same as the primary GID of the user, this would allow unauthorized
access to the users files, and users that share the same group may not be
able to access files that they legitimately should. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Get all local users from /etc/passwd
ansible.builtin.getent:
database: passwd
split: ':'
tags:
- CCE-83434-1
- DISA-STIG-RHEL-08-010740
- file_groupownership_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Create local_users variable from the getent output
ansible.builtin.set_fact:
local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
tags:
- CCE-83434-1
- DISA-STIG-RHEL-08-010740
- file_groupownership_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Test for existence of home directories to avoid creating them, but only fixing
group ownership
ansible.builtin.stat:
path: '{{ item.value[4] }}'
register: path_exists
loop: '{{ local_users }}'
when:
- item.value[2]|int >= 1000
- item.value[2]|int != 65534
tags:
- CCE-83434-1
- DISA-STIG-RHEL-08-010740
- file_groupownership_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure interactive local users are the group-owners of their respective home
directories
ansible.builtin.file:
path: '{{ item.0.value[4] }}'
group: '{{ item.0.value[2] }}'
loop: '{{ local_users|zip(path_exists.results)|list }}'
when: item.1.stat is defined and item.1.stat.exists
tags:
- CCE-83434-1
- DISA-STIG-RHEL-08-010740
- file_groupownership_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
awk -F':' '{ if ($4 >= 1000 && $4 != 65534) system("chgrp -f " $4" "$6) }' /etc/passwd
|
All Interactive User Home Directories Must Be Owned By The Primary User
[ref]ruleChange the owner of interactive users home directories to that correct
owner. To change the owner of a interactive users home directory, use
the following command:
$ sudo chown USER /home/USER
This rule ensures every home directory related to an interactive user is
owned by an interactive user. It also ensures that interactive users are
owners of one and only one home directory.Warning:
Due to OVAL limitation, this rule can report a false negative in a
specific situation where two interactive users swap the ownership of
their respective home directories. Rationale:If a local interactive user does not own their home directory, unauthorized
users could access or modify the user's files, and the users may not be able to
access their own files. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Get all local users from /etc/passwd
ansible.builtin.getent:
database: passwd
split: ':'
tags:
- CCE-86131-0
- file_ownership_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Create local_users variable from the getent output
ansible.builtin.set_fact:
local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
tags:
- CCE-86131-0
- file_ownership_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Test for existence home directories to avoid creating them, but only fixing
ownership
ansible.builtin.stat:
path: '{{ item.value[4] }}'
register: path_exists
loop: '{{ local_users }}'
when:
- item.value[1]|int >= 1000
- item.value[1]|int != 65534
tags:
- CCE-86131-0
- file_ownership_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure interactive local users are the owners of their respective home directories
ansible.builtin.file:
path: '{{ item.0.value[4] }}'
owner: '{{ item.0.value[1] }}'
loop: '{{ local_users|zip(path_exists.results)|list }}'
when: item.1.stat is defined and item.1.stat.exists
tags:
- CCE-86131-0
- file_ownership_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
awk -F':' '{ if ($3 >= 1000 && $3 != 65534) system("chown -f " $3" "$6) }' /etc/passwd
|
All Interactive User Home Directories Must Have mode 0750 Or Less Permissive
[ref]ruleChange the mode of interactive users home directories to 0750 . To
change the mode of interactive users home directory, use the
following command:
$ sudo chmod 0750 /home/USER Rationale:Excessive permissions on local interactive user home directories may allow
unauthorized access to user files by other users. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Get all local users from /etc/passwd
ansible.builtin.getent:
database: passwd
split: ':'
tags:
- CCE-84038-9
- DISA-STIG-RHEL-08-010730
- file_permissions_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Create local_users variable from the getent output
ansible.builtin.set_fact:
local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
tags:
- CCE-84038-9
- DISA-STIG-RHEL-08-010730
- file_permissions_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Test for existence home directories to avoid creating them.
ansible.builtin.stat:
path: '{{ item.value[4] }}'
register: path_exists
loop: '{{ local_users }}'
when:
- item.value[1]|int >= 1000
- item.value[1]|int != 65534
tags:
- CCE-84038-9
- DISA-STIG-RHEL-08-010730
- file_permissions_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure interactive local users have proper permissions on their respective
home directories
ansible.builtin.file:
path: '{{ item.0.value[4] }}'
mode: u-s,g-w-s,o=-
follow: false
recurse: false
loop: '{{ local_users|zip(path_exists.results)|list }}'
when: item.1.stat is defined and item.1.stat.exists
tags:
- CCE-84038-9
- DISA-STIG-RHEL-08-010730
- file_permissions_home_directories
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
for home_dir in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534) print $6 }' /etc/passwd); do
# Only update the permissions when necessary. This will avoid changing the inode timestamp when
# the permission is already defined as expected, therefore not impacting in possible integrity
# check systems that also check inodes timestamps.
find "$home_dir" -maxdepth 0 -perm /7027 -exec chmod u-s,g-w-s,o=- {} \;
done
|
System Accounting with auditd
[ref]groupThe audit service provides substantial capabilities
for recording system activities. By default, the service audits about
SELinux AVC denials and certain types of security-relevant events
such as system logins, account modifications, and authentication
events performed by programs such as sudo.
Under its default configuration, auditd has modest disk space
requirements, and should not noticeably impact system performance.
NOTE: The Linux Audit daemon auditd can be configured to use
the augenrules program to read audit rules files (*.rules )
located in /etc/audit/rules.d location and compile them to create
the resulting form of the /etc/audit/audit.rules configuration file
during the daemon startup (default configuration). Alternatively, the auditd
daemon can use the auditctl utility to read audit rules from the
/etc/audit/audit.rules configuration file during daemon startup,
and load them into the kernel. The expected behavior is configured via the
appropriate ExecStartPost directive setting in the
/usr/lib/systemd/system/auditd.service configuration file.
To instruct the auditd daemon to use the augenrules program
to read audit rules (default configuration), use the following setting:
ExecStartPost=-/sbin/augenrules --load
in the /usr/lib/systemd/system/auditd.service configuration file.
In order to instruct the auditd daemon to use the auditctl
utility to read audit rules, use the following setting:
ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules
in the /usr/lib/systemd/system/auditd.service configuration file.
Refer to [Service] section of the /usr/lib/systemd/system/auditd.service
configuration file for further details.
Government networks often have substantial auditing
requirements and auditd can be configured to meet these
requirements.
Examining some example audit records demonstrates how the Linux audit system
satisfies common requirements.
The following example from Red Hat Enterprise Linux 7 Documentation available at
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/selinux_users_and_administrators_guide/index#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages
shows the substantial amount of information captured in a
two typical "raw" audit messages, followed by a breakdown of the most important
fields. In this example the message is SELinux-related and reports an AVC
denial (and the associated system call) that occurred when the Apache HTTP
Server attempted to access the /var/www/html/file1 file (labeled with
the samba_share_t type):
type=AVC msg=audit(1226874073.147:96): avc: denied { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file
type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
msg=audit(1226874073.147:96) - The number in parentheses is the unformatted time stamp (Epoch time)
for the event, which can be converted to standard time by using the
date command.
{ getattr } - The item in braces indicates the permission that was denied.
getattr
indicates the source process was trying to read the target file's status information.
This occurs before reading files. This action is denied due to the file being
accessed having the wrong label. Commonly seen permissions include getattr ,
read , and write .
comm="httpd" - The executable that launched the process. The full path of the executable is
found in the
exe= section of the system call (SYSCALL ) message,
which in this case, is exe="/usr/sbin/httpd" .
path="/var/www/html/file1" - The path to the object (target) the process attempted to access.
scontext="unconfined_u:system_r:httpd_t:s0" - The SELinux context of the process that attempted the denied action. In
this case, it is the SELinux context of the Apache HTTP Server, which is running
in the
httpd_t domain.
tcontext="unconfined_u:object_r:samba_share_t:s0" - The SELinux context of the object (target) the process attempted to access.
In this case, it is the SELinux context of
file1 . Note: the samba_share_t
type is not accessible to processes running in the httpd_t domain.
- From the system call (
SYSCALL ) message, two items are of interest:
success=no : indicates whether the denial (AVC) was enforced or not.
success=no indicates the system call was not successful (SELinux denied
access). success=yes indicates the system call was successful - this can
be seen for permissive domains or unconfined domains, such as initrc_t
and kernel_t .
exe="/usr/sbin/httpd" : the full path to the executable that launched
the process, which in this case, is exe="/usr/sbin/httpd" .
|
contains 50 rules |
Configure auditd Rules for Comprehensive Auditing
[ref]groupThe auditd program can perform comprehensive
monitoring of system activity. This section describes recommended
configuration settings for comprehensive auditing, but a full
description of the auditing system's capabilities is beyond the
scope of this guide. The mailing list linux-audit@redhat.com exists
to facilitate community discussion of the auditing system.
The audit subsystem supports extensive collection of events, including:
- Tracing of arbitrary system calls (identified by name or number)
on entry or exit.
- Filtering by PID, UID, call success, system call argument (with
some limitations), etc.
- Monitoring of specific files for modifications to the file's
contents or metadata.
Auditing rules at startup are controlled by the file /etc/audit/audit.rules .
Add rules to it to meet the auditing requirements for your organization.
Each line in /etc/audit/audit.rules represents a series of arguments
that can be passed to auditctl and can be individually tested
during runtime. See documentation in /usr/share/doc/audit-VERSION and
in the related man pages for more details.
If copying any example audit rulesets from /usr/share/doc/audit-VERSION ,
be sure to comment out the
lines containing arch= which are not appropriate for your system's
architecture. Then review and understand the following rules,
ensuring rules are activated as needed for the appropriate
architecture.
After reviewing all the rules, reading the following sections, and
editing as needed, the new rules can be activated as follows:
$ sudo service auditd restart |
contains 41 rules |
Record Events that Modify the System's Discretionary Access Controls
[ref]groupAt a minimum, the audit system should collect file permission
changes for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to /etc/audit/audit.rules :
-a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If your system is 64 bit then these lines should be duplicated and the
arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod |
contains 13 rules |
Record Events that Modify the System's Discretionary Access Controls - chmod
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80685-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030490, 4.1.9, SV-230456r810462_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80685-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit chmod tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80685-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chmod for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80685-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chmod for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80685-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="chmod"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - chown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80686-9 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030480, 4.1.9, SV-230455r810459_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80686-9
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit chown tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80686-9
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chown for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80686-9
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chown for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80686-9
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="chown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fchmod
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80687-7 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030490, 4.1.9, SV-230456r810462_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80687-7
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchmod tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80687-7
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmod for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80687-7
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmod for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80687-7
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchmod"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fchmodat
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80688-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030490, 4.1.9, SV-230456r810462_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80688-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchmodat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80688-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmodat for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80688-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmodat for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80688-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030490
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchmodat"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fchown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80689-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030480, 4.1.9, SV-230455r810459_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80689-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchown tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80689-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchown for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80689-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchown for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80689-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fchownat
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80690-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030480, 4.1.9, SV-230455r810459_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80690-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchownat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80690-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchownat for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80690-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchownat for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80690-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchownat"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fremovexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S fremovexattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S fremovexattr -F auid=0 -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S fremovexattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S fremovexattr -F auid=0 -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80691-9 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030200, 4.1.9, SV-230413r810463_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80691-9
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fremovexattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80691-9
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fremovexattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80691-9
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fremovexattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80691-9
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fremovexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid=0"
SYSCALL="fremovexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fsetxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S fsetxattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S fsetxattr -F auid=0 -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S fsetxattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S fsetxattr -F auid=0 -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80692-7 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030200, 4.1.9, SV-230413r810463_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80692-7
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fsetxattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80692-7
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fsetxattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80692-7
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fsetxattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80692-7
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fsetxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid=0"
SYSCALL="fsetxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - lchown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80693-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030480, 4.1.9, SV-230455r810459_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80693-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lchown tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80693-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lchown for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80693-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lchown for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80693-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030480
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lchown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - lremovexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S lremovexattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S lremovexattr -F auid=0 -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S lremovexattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S lremovexattr -F auid=0 -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80694-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030200, 4.1.9, SV-230413r810463_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80694-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lremovexattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80694-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lremovexattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80694-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lremovexattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80694-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lremovexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid=0"
SYSCALL="lremovexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - lsetxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S lsetxattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S lsetxattr -F auid=0 -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S lsetxattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S lsetxattr -F auid=0 -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80695-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030200, 4.1.9, SV-230413r810463_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80695-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lsetxattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80695-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lsetxattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80695-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lsetxattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80695-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lsetxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid=0"
SYSCALL="lsetxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - removexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured to use the augenrules
program to read audit rules during daemon startup (the default), add the
following line to a file with suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S removexattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S removexattr -F auid=0 -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S removexattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S removexattr -F auid=0 -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80696-8 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030200, 4.1.9, SV-230413r810463_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80696-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit removexattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80696-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for removexattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80696-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for removexattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80696-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="removexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid=0"
SYSCALL="removexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - setxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S setxattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S setxattr -F auid=0 -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S setxattr -F auid=0 -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S setxattr -F auid=0 -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-80697-6 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940, RHEL-08-030200, 4.1.9, SV-230413r810463_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80697-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit setxattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80697-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for setxattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80697-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for setxattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid=0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid=0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid=0 -F
key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80697-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="setxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid=0"
SYSCALL="setxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record File Deletion Events by User
[ref]groupAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete |
contains 4 rules |
Ensure auditd Collects File Deletion Events by User - rename
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-80703-2 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-OS-000466-VMM-001870, SRG-OS-000468-VMM-001890, RHEL-08-030361, 4.1.14, SV-230439r810465_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80703-2
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit rename tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80703-2
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rename for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rename in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rename in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80703-2
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rename for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rename in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rename in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80703-2
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="rename"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects File Deletion Events by User - renameat
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-80704-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-OS-000466-VMM-001870, SRG-OS-000468-VMM-001890, RHEL-08-030361, 4.1.14, SV-230439r810465_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80704-0
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit renameat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80704-0
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of renameat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of renameat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80704-0
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of renameat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of renameat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80704-0
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="renameat"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects File Deletion Events by User - unlink
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-80706-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-OS-000466-VMM-001870, SRG-OS-000468-VMM-001890, RHEL-08-030361, 4.1.14, SV-230439r810465_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80706-5
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit unlink tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80706-5
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlink for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlink in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlink in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80706-5
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlink for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlink in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlink in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80706-5
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="unlink"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects File Deletion Events by User - unlinkat
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-80707-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-OS-000466-VMM-001870, SRG-OS-000468-VMM-001890, RHEL-08-030361, 4.1.14, SV-230439r810465_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80707-3
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit unlinkat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80707-3
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlinkat for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlinkat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlinkat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80707-3
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlinkat for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlinkat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlinkat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80707-3
- DISA-STIG-RHEL-08-030361
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_file_deletion_events_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="unlinkat"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Unauthorized Access Attempts Events to Files (unsuccessful)
[ref]groupAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to /etc/audit/audit.rules :
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If your system is 64 bit then these lines should be duplicated and the
arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access |
contains 5 rules |
Record Unsuccessful Access Attempts to Files - creat
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-80751-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830, RHEL-08-030420, 4.1.10, SV-230449r810455_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80751-1
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit creat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80751-1
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for creat EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80751-1
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for creat EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80751-1
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for creat EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80751-1
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for creat EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80751-1
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="creat"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EACCES"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EPERM"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Unsuccessful Access Attempts to Files - ftruncate
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exiu=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-80752-9 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830, RHEL-08-030420, 4.1.10, SV-230449r810455_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80752-9
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit ftruncate tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80752-9
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for ftruncate EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80752-9
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for ftruncate EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80752-9
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for ftruncate EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80752-9
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for ftruncate EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80752-9
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="ftruncate"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EACCES"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EPERM"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Unsuccessful Access Attempts to Files - open
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-80753-7 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830, RHEL-08-030420, 4.1.10, SV-230449r810455_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80753-7
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit open tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80753-7
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80753-7
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80753-7
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80753-7
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80753-7
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="open"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EACCES"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EPERM"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Unsuccessful Access Attempts to Files - openat
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-80754-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830, RHEL-08-030420, 4.1.10, SV-230449r810455_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80754-5
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit openat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80754-5
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for openat EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80754-5
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for openat EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80754-5
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for openat EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80754-5
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for openat EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80754-5
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="openat"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EACCES"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EPERM"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Unsuccessful Access Attempts to Files - truncate
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-80756-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830, RHEL-08-030420, 4.1.10, SV-230449r810455_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80756-0
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit truncate tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80756-0
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for truncate EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80756-0
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for truncate EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80756-0
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for truncate EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80756-0
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for truncate EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80756-0
- DISA-STIG-RHEL-08-030420
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="truncate"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EACCES"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EPERM"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Information on Kernel Modules Loading and Unloading
[ref]groupTo capture kernel module loading and unloading events, use following lines, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module,delete_module -F key=modules
Place to add the lines depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl utility,
add the lines to file /etc/audit/audit.rules . |
contains 2 rules |
Ensure auditd Collects Information on Kernel Module Unloading - delete_module
[ref]ruleTo capture kernel module unloading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S delete_module -F auid>=1000 -F auid!=unset -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules .Rationale:The removal of kernel modules can be used to alter the behavior of
the kernel and potentially introduce malicious code into kernel space. It is important
to have an audit trail of modules that have been introduced into the kernel. Identifiers:
CCE-80711-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SRG-OS-000477-VMM-001970, RHEL-08-030390, 4.1.15, SV-230446r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80711-5
- DISA-STIG-RHEL-08-030390
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_delete
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set architecture for audit delete_module tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80711-5
- DISA-STIG-RHEL-08-030390
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_delete
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for delete_module for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- delete_module
syscall_grouping: []
- name: Check existence of delete_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- delete_module
syscall_grouping: []
- name: Check existence of delete_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80711-5
- DISA-STIG-RHEL-08-030390
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_delete
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for delete_module for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- delete_module
syscall_grouping: []
- name: Check existence of delete_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- delete_module
syscall_grouping: []
- name: Check existence of delete_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80711-5
- DISA-STIG-RHEL-08-030390
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_delete
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
# it's required on a 64-bit system to check also for the presence
# of 32-bit's equivalent of the corresponding rule.
# (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="delete_module"
KEY="modules"
SYSCALL_GROUPING="delete_module"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20delete_module%20-k%20module-change%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20delete_module%20-k%20module-change%0A
mode: 0600
path: /etc/audit/rules.d/75-kernel-module-loading-delete.rules
overwrite: true
|
Ensure auditd Collects Information on Kernel Module Loading - init_module
[ref]ruleTo capture kernel module loading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module -F auid>=1000 -F auid!=unset -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules .Rationale:The addition of kernel modules can be used to alter the behavior of
the kernel and potentially introduce malicious code into kernel space. It is important
to have an audit trail of modules that have been introduced into the kernel. Identifiers:
CCE-80713-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SRG-OS-000477-VMM-001970, RHEL-08-030360, 4.1.15, SV-230438r810464_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80713-1
- DISA-STIG-RHEL-08-030360
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_init
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set architecture for audit init_module tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80713-1
- DISA-STIG-RHEL-08-030360
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_init
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for init_module for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of init_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of init_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80713-1
- DISA-STIG-RHEL-08-030360
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_init
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for init_module for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of init_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of init_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80713-1
- DISA-STIG-RHEL-08-030360
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_init
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
# it's required on a 64-bit system to check also for the presence
# of 32-bit's equivalent of the corresponding rule.
# (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="init_module"
KEY="modules"
SYSCALL_GROUPING="init_module finit_module"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20init_module%20-k%20module-change%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20init_module%20-k%20module-change%0A
mode: 0600
path: /etc/audit/rules.d/75-kernel-module-loading-init.rules
overwrite: true
|
Record Attempts to Alter Logon and Logout Events
[ref]groupThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock/ -p wa -k logins
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock/ -p wa -k logins
-w /var/log/lastlog -p wa -k logins |
contains 2 rules |
Record Attempts to Alter Logon and Logout Events - faillock
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/run/faillock -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/run/faillock -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-80718-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218, SRG-OS-000473-VMM-001930, SRG-OS-000470-VMM-001900, 4.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80718-0
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k logins$
patterns: '*.rules'
register: find_faillock
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80718-0
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/logins.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- find_faillock.matched is defined and find_faillock.matched == 0
tags:
- CCE-80718-0
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_faillock.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_faillock.matched is defined and find_faillock.matched > 0
tags:
- CCE-80718-0
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the faillock rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/run/faillock -p wa -k logins
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80718-0
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the faillock rule in /etc/audit/audit.rules
lineinfile:
line: -w /var/run/faillock -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80718-0
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/run/faillock" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/faillock $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/faillock$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/faillock -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/run/faillock" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/run/faillock" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/faillock $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/faillock$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/faillock -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Logon and Logout Events - lastlog
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-80719-8 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000470-GPOS-00214, SRG-OS-000473-VMM-001930, SRG-OS-000470-VMM-001900, RHEL-08-030600, 4.1.4, SV-230467r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80719-8
- DISA-STIG-RHEL-08-030600
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k logins$
patterns: '*.rules'
register: find_lastlog
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80719-8
- DISA-STIG-RHEL-08-030600
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/logins.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- find_lastlog.matched is defined and find_lastlog.matched == 0
tags:
- CCE-80719-8
- DISA-STIG-RHEL-08-030600
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_lastlog.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_lastlog.matched is defined and find_lastlog.matched > 0
tags:
- CCE-80719-8
- DISA-STIG-RHEL-08-030600
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the lastlog rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/lastlog -p wa -k logins
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80719-8
- DISA-STIG-RHEL-08-030600
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the lastlog rule in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/lastlog -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80719-8
- DISA-STIG-RHEL-08-030600
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/lastlog" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Records Events that Modify Date and Time Information
[ref]groupArbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time. All changes to the system
time should be audited. |
contains 4 rules |
Record attempts to alter time through adjtimex
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be
used for better reporting capability through ausearch and aureport. Multiple
system calls can be defined on the same line to save space if desired, but is
not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-80745-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 4.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80745-3
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80745-3
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for adjtimex for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80745-3
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for adjtimex for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- name: Check existence of adjtimex in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80745-3
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# Create expected audit group and audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday stime"
SYSCALL_GROUPING="adjtimex settimeofday stime"
elif [ ${ARCH} = "b64" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday"
SYSCALL_GROUPING="adjtimex settimeofday"
fi
OTHER_FILTERS=""
AUID_FILTERS=""
KEY="audit_time_rules"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20adjtimex%20-k%20audit_time_rules%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20adjtimex%20-k%20audit_time_rules%0A }}
mode: 0600
path: /etc/audit/rules.d/75-syscall-adjtimex.rules
overwrite: true
|
Record Attempts to Alter Time Through clock_settime
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport.
Multiple system calls can be defined on the same line to save space if
desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-80746-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 4.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80746-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80746-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for clock_settime for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80746-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for clock_settime for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80746-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F a0=0x0"
AUID_FILTERS=""
SYSCALL="clock_settime"
KEY="time-change"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20clock_settime%20-F%20a0%3D0x0%20-k%20time-change%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20clock_settime%20-F%20a0%3D0x0%20-k%20time-change%0A }}
mode: 0600
path: /etc/audit/rules.d/75-syscall-clock-settime.rules
overwrite: true
|
Record Attempts to Alter Time Through stime
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit
lookup table, the corresponding "-F arch=b64" form of this rule is not expected
to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule
form itself is sufficient for both 32 bit and 64 bit systems). If the
auditd daemon is configured to use the auditctl utility to
read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit
lookup table, the corresponding "-F arch=b64" form of this rule is not expected
to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule
form itself is sufficient for both 32 bit and 64 bit systems). The -k option
allows for the specification of a key in string form that can be used for
better reporting capability through ausearch and aureport. Multiple system
calls can be defined on the same line to save space if desired, but is not
required. See an example of multiple combined system calls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-80748-7 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 4.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80748-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_stime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for stime syscall for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- stime
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of stime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- stime
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of stime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80748-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_stime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# Create expected audit group and audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday stime"
SYSCALL_GROUPING="adjtimex settimeofday stime"
elif [ ${ARCH} = "b64" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday"
SYSCALL_GROUPING="adjtimex settimeofday"
fi
OTHER_FILTERS=""
AUID_FILTERS=""
KEY="audit_time_rules"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20stime%20-k%20audit_time_rules%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20stime%20-k%20audit_time_rules%0A }}
mode: 0600
path: /etc/audit/rules.d/75-syscall-stime.rules
overwrite: true
|
Record Attempts to Alter the localtime File
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d :
-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport and
should always be used.Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-80749-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 4.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80749-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/localtime already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80749-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_time_rules
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80749-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_time_rules.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80749-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80749-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/localtime in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/localtime -p wa -k audit_time_rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80749-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/localtime already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80749-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/localtime in /etc/audit/audit.rules
lineinfile:
line: -w /etc/localtime -p wa -k audit_time_rules
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80749-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_time_rules.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/localtime" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_time_rules.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_time_rules.rules"
# If the audit_time_rules.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -w%20/etc/localtime%20-p%20wa%20-k%20audit_time_rules%0A }}
mode: 0600
path: /etc/audit/rules.d/75-etclocaltime-wa-audit_time_rules.rules
overwrite: true
|
Make the auditd Configuration Immutable
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d in order to make the auditd configuration
immutable:
-e 2
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file in order to make the auditd configuration
immutable:
-e 2
With this setting, a reboot will be required to change any audit rules.Rationale:Making the audit configuration immutable prevents accidental as
well as malicious modification of the audit rules, although it may be
problematic if legitimate changes are needed during system
operation. Identifiers:
CCE-80708-1 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO01.06, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.4.3, CCI-000162, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.310(a)(2)(iv), 164.312(d), 164.310(d)(2)(iii), 164.312(b), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.5.2, SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, RHEL-08-030121, 4.1.17, SV-230402r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80708-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030121
- NIST-800-171-3.3.1
- NIST-800-171-3.4.3
- NIST-800-53-AC-6(9)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.2
- audit_rules_immutable
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Collect all files from /etc/audit/rules.d with .rules extension
find:
paths: /etc/audit/rules.d/
patterns: '*.rules'
register: find_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80708-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030121
- NIST-800-171-3.3.1
- NIST-800-171-3.4.3
- NIST-800-53-AC-6(9)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.2
- audit_rules_immutable
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Remove the -e option from all Audit config files
lineinfile:
path: '{{ item }}'
regexp: ^\s*(?:-e)\s+.*$
state: absent
loop: '{{ find_rules_d.files | map(attribute=''path'') | list + [''/etc/audit/audit.rules'']
}}'
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80708-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030121
- NIST-800-171-3.3.1
- NIST-800-171-3.4.3
- NIST-800-53-AC-6(9)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.2
- audit_rules_immutable
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add Audit -e option into /etc/audit/rules.d/immutable.rules and /etc/audit/audit.rules
lineinfile:
path: '{{ item }}'
create: true
line: -e 2
mode: o-rwx
loop:
- /etc/audit/audit.rules
- /etc/audit/rules.d/immutable.rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80708-1
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030121
- NIST-800-171-3.3.1
- NIST-800-171-3.4.3
- NIST-800-53-AC-6(9)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.2
- audit_rules_immutable
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Traverse all of:
#
# /etc/audit/audit.rules, (for auditctl case)
# /etc/audit/rules.d/*.rules (for augenrules case)
#
# files to check if '-e .*' setting is present in that '*.rules' file already.
# If found, delete such occurrence since auditctl(8) manual page instructs the
# '-e 2' rule should be placed as the last rule in the configuration
find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -exec sed -i '/-e[[:space:]]\+.*/d' {} ';'
# Append '-e 2' requirement at the end of both:
# * /etc/audit/audit.rules file (for auditctl case)
# * /etc/audit/rules.d/immutable.rules (for augenrules case)
for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
do
echo '' >> $AUDIT_FILE
echo '# Set the audit.rules configuration immutable per security requirements' >> $AUDIT_FILE
echo '# Reboot is required to change audit rules once this setting is applied' >> $AUDIT_FILE
echo '-e 2' >> $AUDIT_FILE
chmod o-rwx $AUDIT_FILE
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,-e%202%0A
mode: 0600
path: /etc/audit/rules.d/90-immutable.rules
overwrite: true
|
Record Events that Modify the System's Mandatory Access Controls
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-w /etc/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/selinux/ -p wa -k MAC-policy Rationale:The system's mandatory access policy (SELinux) should not be
arbitrarily changed by anything other than administrator action. All changes to
MAC policy should be audited. Identifiers:
CCE-80721-4 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.8, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 4.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80721-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80721-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key MAC-policy
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)MAC-policy$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80721-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/MAC-policy.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/MAC-policy.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80721-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80721-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/selinux/ in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/selinux/ -p wa -k MAC-policy
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80721-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80721-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/selinux/ in /etc/audit/audit.rules
lineinfile:
line: -w /etc/selinux/ -p wa -k MAC-policy
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80721-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/selinux/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/selinux/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/selinux/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/selinux/ -p wa -k MAC-policy" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/MAC-policy.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/selinux/" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/MAC-policy.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/MAC-policy.rules"
# If the MAC-policy.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/selinux/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/selinux/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/selinux/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/selinux/ -p wa -k MAC-policy" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -w%20/etc/selinux/%20-p%20wa%20-k%20MAC-policy%0A }}
mode: 0600
path: /etc/audit/rules.d/75-etcselinux-wa-MAC-policy.rules
overwrite: true
|
Ensure auditd Collects Information on Exporting to Media (successful)
[ref]ruleAt a minimum, the audit system should collect media exportation
events for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export Rationale:The unauthorized exportation of data to external media could result in an information leak
where classified information, Privacy Act information, and intellectual property could be lost. An audit
trail should be created each time a filesystem is mounted to help identify and guard against information
loss. Identifiers:
CCE-80722-2 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, RHEL-08-030302, 4.1.12, SV-230425r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80722-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030302
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit mount tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80722-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030302
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for mount for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80722-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030302
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for mount for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80722-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030302
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="mount"
KEY="perm_mod"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Network Environment
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification Rationale:The network environment should not be modified by anything other
than administrator action. Any change to network parameters should be
audited. Identifiers:
CCE-80723-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.5.5, 4.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remediate audit rules for network configuration for x86
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remediate audit rules for network configuration for x86_64
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue in /etc/audit/audit.rules
lineinfile:
line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue.net in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue.net in /etc/audit/audit.rules
lineinfile:
line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/hosts already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/hosts in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/hosts already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/hosts in /etc/audit/audit.rules
lineinfile:
line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sysconfig/network in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sysconfig/network in /etc/audit/audit.rules
lineinfile:
line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80723-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS=""
SYSCALL="sethostname setdomainname"
KEY="audit_rules_networkconfig_modification"
SYSCALL_GROUPING="sethostname setdomainname"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
# Then perform the remediations for the watch rules
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue.net" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/hosts" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sysconfig/network" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Process and Session Initiation Information
[ref]ruleThe audit system already collects process information for all
users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-80742-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, 0582, 0584, 05885, 0586, 0846, 0957, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 4.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/run/utmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/run/utmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/run/utmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/run/utmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/btmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/btmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/btmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/btmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/wtmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/wtmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/wtmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/wtmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-80742-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/run/utmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/btmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/wtmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %0A-w%20/var/run/utmp%20-p%20wa%20-k%20session%0A-w%20/var/log/btmp%20-p%20wa%20-k%20session%0A-w%20/var/log/wtmp%20-p%20wa%20-k%20session%0A }}
mode: 0600
path: /etc/audit/rules.d/75-audit-session-events.rules
overwrite: true
|
Ensure auditd Collects System Administrator Actions
[ref]ruleAt a minimum, the audit system should collect administrator actions
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d :
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions Rationale:The actions taken by system administrators should be audited to keep a record
of what was executed on the system, as well as, for accountability purposes. Identifiers:
CCE-80743-8 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(7)(b), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.2, Req-10.2.5.b, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000462-VMM-001840, SRG-OS-000471-VMM-001910, 4.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80743-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for audit rule entries for sysadmin actions
find:
paths: /etc/audit/rules.d
recurse: false
contains: ^.*/etc/sudoers.*$
patterns: '*.rules'
register: find_audit_sysadmin_actions
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80743-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
set_fact:
all_sysadmin_actions_files:
- /etc/audit/rules.d/actions.rules
when:
- '"audit" in ansible_facts.packages'
- find_audit_sysadmin_actions.matched is defined and find_audit_sysadmin_actions.matched
== 0
tags:
- CCE-80743-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_sysadmin_actions_files:
- '{{ find_audit_sysadmin_actions.files | map(attribute=''path'') | list | first
}}'
when:
- '"audit" in ansible_facts.packages'
- find_audit_sysadmin_actions.matched is defined and find_audit_sysadmin_actions.matched
> 0
tags:
- CCE-80743-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers rule in rules.d
lineinfile:
path: '{{ all_sysadmin_actions_files[0] }}'
line: -w /etc/sudoers -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80743-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers.d rule in rules.d
lineinfile:
path: '{{ all_sysadmin_actions_files[0] }}'
line: -w /etc/sudoers.d/ -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80743-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers in audit.rules
lineinfile:
path: /etc/audit/audit.rules
line: -w /etc/sudoers -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80743-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers.d in audit.rules
lineinfile:
path: /etc/audit/audit.rules
line: -w /etc/sudoers.d/ -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80743-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/actions.rules"
# If the actions.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers.d/" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/actions.rules"
# If the actions.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -w%20/etc/sudoers.d/%20-p%20wa%20-k%20actions%0A-w%20/etc/sudoers%20-p%20wa%20-k%20actions%0A }}
mode: 0600
path: /etc/audit/rules.d/75-audit-sysadmin-actions.rules
overwrite: true
|
Record Events that Modify User/Group Information - /etc/group
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-80758-6 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960, RHEL-08-030170, 4.1.11, SV-230408r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80758-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030170
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit group tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80758-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030170
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_group
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80758-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030170
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_group.matched is defined and find_group.matched == 0
tags:
- CCE-80758-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030170
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_group.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_group.matched is defined and find_group.matched > 0
tags:
- CCE-80758-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030170
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the group rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/group -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80758-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030170
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the group rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/group -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80758-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030170
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/group" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/group" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/group" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/gshadow
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-80759-4 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960, RHEL-08-030160, 4.1.11, SV-230407r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80759-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030160
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit gshadow tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80759-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030160
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_gshadow
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80759-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030160
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_gshadow.matched is defined and find_gshadow.matched == 0
tags:
- CCE-80759-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030160
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_gshadow.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_gshadow.matched is defined and find_gshadow.matched > 0
tags:
- CCE-80759-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030160
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the gshadow rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80759-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030160
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the gshadow rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80759-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030160
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/gshadow" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/security/opasswd
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-80760-2 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000476-GPOS-00221, SRG-OS-000463-GPOS-00207, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960, RHEL-08-030140, 4.1.11, SV-230405r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80760-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030140
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit opasswd tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80760-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030140
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_opasswd
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80760-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030140
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_opasswd.matched is defined and find_opasswd.matched == 0
tags:
- CCE-80760-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030140
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_opasswd.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_opasswd.matched is defined and find_opasswd.matched > 0
tags:
- CCE-80760-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030140
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the opasswd rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80760-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030140
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the opasswd rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80760-2
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030140
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/security/opasswd" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/passwd
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-80761-0 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000274-GPOS-00104, SRG-OS-000275-GPOS-00105, SRG-OS-000276-GPOS-00106, SRG-OS-000277-GPOS-00107, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960, RHEL-08-030150, 4.1.11, SV-230406r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80761-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030150
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit passwd tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80761-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030150
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_passwd
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80761-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030150
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_passwd.matched is defined and find_passwd.matched == 0
tags:
- CCE-80761-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030150
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_passwd.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_passwd.matched is defined and find_passwd.matched > 0
tags:
- CCE-80761-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030150
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the passwd rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80761-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030150
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the passwd rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80761-0
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030150
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/passwd" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/shadow
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-80762-8 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960, RHEL-08-030130, 4.1.11, SV-230404r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80762-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit shadow tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80762-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_shadow
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80762-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_shadow.matched is defined and find_shadow.matched == 0
tags:
- CCE-80762-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_shadow.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_shadow.matched is defined and find_shadow.matched > 0
tags:
- CCE-80762-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the shadow rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80762-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the shadow rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80762-8
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/shadow" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure auditd Data Retention
[ref]groupThe audit system writes data to /var/log/audit/audit.log . By default,
auditd rotates 5 logs by size (6MB), retaining a maximum of 30MB of
data in total, and refuses to write entries when the disk is too
full. This minimizes the risk of audit data filling its partition
and impacting other services. This also minimizes the risk of the audit
daemon temporarily disabling the system if it cannot write audit log (which
it can be configured to do).
For a busy
system or a system which is thoroughly auditing system activity, the default settings
for data retention may be
insufficient. The log file size needed will depend heavily on what types
of events are being audited. First configure auditing to log all the events of
interest. Then monitor the log size manually for awhile to determine what file
size will allow you to keep the required data for the correct time period.
Using a dedicated partition for /var/log/audit prevents the
auditd logs from disrupting system functionality if they fill, and,
more importantly, prevents other activity in /var from filling the
partition and stopping the audit trail. (The audit logs are size-limited and
therefore unlikely to grow without bound unless configured to do so.) Some
machines may have requirements that no actions occur which cannot be audited.
If this is the case, then auditd can be configured to halt the machine
if it runs out of space. Note: Since older logs are rotated,
configuring auditd this way does not prevent older logs from being
rotated away before they can be viewed.
If your system is configured to halt when logging cannot be performed, make
sure this can never happen under normal circumstances! Ensure that
/var/log/audit is on its own partition, and that this partition is
larger than the maximum amount of data auditd will retain
normally. |
contains 5 rules |
Configure auditd mail_acct Action on Low Disk Space
[ref]ruleThe auditd service can be configured to send email to
a designated account in certain situations. Add or correct the following line
in /etc/audit/auditd.conf to ensure that administrators are notified
via email for those situations:
action_mail_acct = root Rationale:Email sent to the root account is typically aliased to the
administrators of the system, who can take appropriate action. Identifiers:
CCE-80678-6 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000139, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, CIP-003-8 R1.3, CIP-003-8 R3, CIP-003-8 R3.1, CIP-003-8 R3.2, CIP-003-8 R3.3, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-5(1), AU-5(a), AU-5(2), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7.a, SRG-OS-000046-GPOS-00022, SRG-OS-000343-GPOS-00134, SRG-OS-000046-VMM-000210, SRG-OS-000343-VMM-001240, RHEL-08-030020, 4.1.2.3, SV-230388r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80678-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030020
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)
- PCI-DSS-Req-10.7.a
- auditd_data_retention_action_mail_acct
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_action_mail_acct # promote to variable
set_fact:
var_auditd_action_mail_acct: !!str root
tags:
- always
- name: Configure auditd mail_acct Action on Low Disk Space
lineinfile:
dest: /etc/audit/auditd.conf
line: action_mail_acct = {{ var_auditd_action_mail_acct }}
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80678-6
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030020
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)
- PCI-DSS-Req-10.7.a
- auditd_data_retention_action_mail_acct
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_action_mail_acct='root'
AUDITCONFIG=/etc/audit/auditd.conf
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "$AUDITCONFIG"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^action_mail_acct")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_action_mail_acct"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^action_mail_acct\\>" "$AUDITCONFIG"; then
"${sed_command[@]}" "s/^action_mail_acct\\>.*/$formatted_output/gi" "$AUDITCONFIG"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80678-6"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$AUDITCONFIG" >> "$AUDITCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure auditd admin_space_left Action on Low Disk Space
[ref]ruleThe auditd service can be configured to take an action
when disk space is running low but prior to running out of space completely.
Edit the file /etc/audit/auditd.conf . Add or modify the following line,
substituting ACTION appropriately:
admin_space_left_action = ACTION
Set this value to single to cause the system to switch to single user
mode for corrective action. Acceptable values also include suspend and
halt . For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined. Details regarding all possible values for ACTION are described in the
auditd.conf man page.Rationale:Administrators should be made aware of an inability to record
audit records. If a separate partition or logical volume of adequate size
is used, running low on space for audit records should never occur. Identifiers:
CCE-80679-4 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000140, CCI-001343, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, SRG-OS-000343-GPOS-00134, 4.1.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80679-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_admin_space_left_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_admin_space_left_action # promote to variable
set_fact:
var_auditd_admin_space_left_action: !!str halt
tags:
- always
- name: Configure auditd admin_space_left Action on Low Disk Space
lineinfile:
dest: /etc/audit/auditd.conf
line: admin_space_left_action = {{ var_auditd_admin_space_left_action }}
regexp: ^\s*admin_space_left_action\s*=\s*.*$
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80679-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_admin_space_left_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_admin_space_left_action='halt'
AUDITCONFIG=/etc/audit/auditd.conf
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "$AUDITCONFIG"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^admin_space_left_action")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_admin_space_left_action"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^admin_space_left_action\\>" "$AUDITCONFIG"; then
"${sed_command[@]}" "s/^admin_space_left_action\\>.*/$formatted_output/gi" "$AUDITCONFIG"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80679-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$AUDITCONFIG" >> "$AUDITCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Configure auditd Max Log File Size
[ref]ruleDetermine the amount of audit data (in megabytes)
which should be retained in each log file. Edit the file
/etc/audit/auditd.conf . Add or modify the following line, substituting
the correct value of 6 for STOREMB:
max_log_file = STOREMB
Set the value to 6 (MB) or higher for general-purpose systems.
Larger values, of course,
support retention of even more audit data.Rationale:The total storage for audit log files must be large enough to retain
log information over the period required. This is a function of the maximum
log file size and the number of logs retained. Identifiers:
CCE-80681-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, CIP-004-6 R2.2.3, CIP-004-6 R3.3, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AU-11, CM-6(a), DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, 4.1.2.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80681-0
- CJIS-5.4.1.1
- NIST-800-53-AU-11
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_max_log_file
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_max_log_file # promote to variable
set_fact:
var_auditd_max_log_file: !!str 6
tags:
- always
- name: Configure auditd Max Log File Size
lineinfile:
dest: /etc/audit/auditd.conf
regexp: ^\s*max_log_file\s*=\s*.*$
line: max_log_file = {{ var_auditd_max_log_file }}
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80681-0
- CJIS-5.4.1.1
- NIST-800-53-AU-11
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_max_log_file
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_max_log_file='6'
AUDITCONFIG=/etc/audit/auditd.conf
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "$AUDITCONFIG"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^max_log_file")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_max_log_file"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^max_log_file\\>" "$AUDITCONFIG"; then
"${sed_command[@]}" "s/^max_log_file\\>.*/$formatted_output/gi" "$AUDITCONFIG"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80681-0"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$AUDITCONFIG" >> "$AUDITCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Configure auditd max_log_file_action Upon Reaching Maximum Log Size
[ref]ruleThe default action to take when the logs reach their maximum size
is to rotate the log files, discarding the oldest one. To configure the action taken
by auditd , add or correct the line in /etc/audit/auditd.conf :
max_log_file_action = ACTION
Possible values for ACTION are described in the auditd.conf man
page. These include:
ignore syslog suspend rotate keep_logs
Set the ACTION to rotate to ensure log rotation
occurs. This is the default. The setting is case-insensitive.Rationale:Automatically rotating logs (by setting this to rotate )
minimizes the chances of the system unexpectedly running out of disk space by
being overwhelmed with log data. However, for systems that must never discard
log data, or which use external processes to transfer it and reclaim space,
keep_logs can be employed. Identifiers:
CCE-80682-8 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, CCI-000140, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, SRG-OS-000047-GPOS-00023, 4.1.2.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80682-8
- CJIS-5.4.1.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_max_log_file_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_max_log_file_action # promote to variable
set_fact:
var_auditd_max_log_file_action: !!str keep_logs
tags:
- always
- name: Configure auditd max_log_file_action Upon Reaching Maximum Log Size
lineinfile:
dest: /etc/audit/auditd.conf
line: max_log_file_action = {{ var_auditd_max_log_file_action }}
regexp: ^\s*max_log_file_action\s*=\s*.*$
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80682-8
- CJIS-5.4.1.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_max_log_file_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_max_log_file_action='keep_logs'
AUDITCONFIG=/etc/audit/auditd.conf
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "$AUDITCONFIG"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^max_log_file_action")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_max_log_file_action"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^max_log_file_action\\>" "$AUDITCONFIG"; then
"${sed_command[@]}" "s/^max_log_file_action\\>.*/$formatted_output/gi" "$AUDITCONFIG"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80682-8"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$AUDITCONFIG" >> "$AUDITCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Configure auditd space_left Action on Low Disk Space
[ref]ruleThe auditd service can be configured to take an action
when disk space starts to run low.
Edit the file /etc/audit/auditd.conf . Modify the following line,
substituting ACTION appropriately:
space_left_action = ACTION
Possible values for ACTION are described in the auditd.conf man page.
These include:
syslog email exec suspend single halt
Set this to email (instead of the default,
which is suspend ) as it is more likely to get prompt attention. Acceptable values
also include suspend , single , and halt .Rationale:Notifying administrators of an impending disk space problem may
allow them to take corrective action prior to any disruption. Identifiers:
CCE-80684-4 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, SRG-OS-000343-GPOS-00134, SRG-OS-000343-VMM-001240, RHEL-08-030731, 4.1.2.3, SV-244543r743878_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80684-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030731
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_space_left_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_space_left_action # promote to variable
set_fact:
var_auditd_space_left_action: !!str email
tags:
- always
- name: Configure auditd space_left Action on Low Disk Space
lineinfile:
dest: /etc/audit/auditd.conf
line: space_left_action = {{ var_auditd_space_left_action }}
regexp: ^\s*space_left_action\s*=\s*.*$
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-80684-4
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030731
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_space_left_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_space_left_action='email'
#
# If space_left_action present in /etc/audit/auditd.conf, change value
# to var_auditd_space_left_action, else
# add "space_left_action = $var_auditd_space_left_action" to /etc/audit/auditd.conf
#
AUDITCONFIG=/etc/audit/auditd.conf
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "$AUDITCONFIG"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^space_left_action")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_space_left_action"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^space_left_action\\>" "$AUDITCONFIG"; then
"${sed_command[@]}" "s/^space_left_action\\>.*/$formatted_output/gi" "$AUDITCONFIG"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80684-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$AUDITCONFIG" >> "$AUDITCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Ensure the audit Subsystem is Installed
[ref]ruleThe audit package should be installed. Rationale:The auditd service is an access monitoring and accounting daemon, watching system calls to audit any access, in comparison with potential local access control policy such as SELinux policy. Identifiers:
CCE-81043-2 References:
BP28(R50), CCI-000172, CCI-001814, CCI-001875, CCI-001877, CCI-001878, CCI-001879, CCI-001880, CCI-001881, CCI-001882, CCI-001889, CCI-001914, CCI-000169, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-7(a), AU-7(1), AU-7(2), AU-14, AU-12(2), AU-2(a), CM-6(a), FAU_GEN.1, SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220, RHEL-08-030180, 4.1.1.1, SV-230411r744000_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure audit is installed
package:
name: audit
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81043-2
- DISA-STIG-RHEL-08-030180
- NIST-800-53-AC-7(a)
- NIST-800-53-AU-12(2)
- NIST-800-53-AU-14
- NIST-800-53-AU-2(a)
- NIST-800-53-AU-7(1)
- NIST-800-53-AU-7(2)
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_audit_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "audit" ; then
yum install -y "audit"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
package --add=audit
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_audit
class install_audit {
package { 'audit':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "audit"
version = "*"
|
Enable auditd Service
[ref]ruleThe auditd service is an essential userspace component of
the Linux Auditing System, as it is responsible for writing audit records to
disk.
The auditd service can be enabled with the following command:
$ sudo systemctl enable auditd.service Rationale:Without establishing what type of events occurred, it would be difficult
to establish, correlate, and investigate the events leading up to an outage or attack.
Ensuring the auditd service is active ensures audit records
generated by the kernel are appropriately recorded.
Additionally, a properly configured audit subsystem ensures that actions of
individual system users can be uniquely traced to those users so they
can be held accountable for their actions. Identifiers:
CCE-80872-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.3.2, 3.3.6, CCI-000126, CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-000154, CCI-000158, CCI-000366, CCI-001464, CCI-001487, CCI-001814, CCI-001876, CCI-002884, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), SI-4(23), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.1, SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220, SRG-OS-000037-VMM-000150, SRG-OS-000063-VMM-000310, SRG-OS-000038-VMM-000160, SRG-OS-000039-VMM-000170, SRG-OS-000040-VMM-000180, SRG-OS-000041-VMM-000190, RHEL-08-030181, 4.1.1.2, SV-244542r818838_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80872-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030181
- NIST-800-171-3.3.1
- NIST-800-171-3.3.2
- NIST-800-171-3.3.6
- NIST-800-53-AC-2(g)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-10
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-14(1)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(23)
- PCI-DSS-Req-10.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_auditd_enabled
- name: Enable service auditd
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service auditd
service:
name: auditd
enabled: 'yes'
state: started
masked: 'no'
when:
- '"audit" in ansible_facts.packages'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"audit" in ansible_facts.packages'
tags:
- CCE-80872-5
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030181
- NIST-800-171-3.3.1
- NIST-800-171-3.3.2
- NIST-800-171-3.3.6
- NIST-800-53-AC-2(g)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-10
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-14(1)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(23)
- PCI-DSS-Req-10.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_auditd_enabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q audit; }; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'auditd.service'
"$SYSTEMCTL_EXEC" start 'auditd.service'
"$SYSTEMCTL_EXEC" enable 'auditd.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: auditd.service
enabled: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include enable_auditd
class enable_auditd {
service {'auditd':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["auditd"]
|
Enable Auditing for Processes Which Start Prior to the Audit Daemon
[ref]ruleTo ensure all processes can be audited, even those which start
prior to the audit daemon, add the argument audit=1 to the default
GRUB 2 command line for the Linux operating system.
To ensure that audit=1 is added as a kernel command line
argument to newly installed kernels, add audit=1 to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... audit=1 ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="audit=1" Rationale:Each process on the system carries an "auditable" flag which indicates whether
its activities can be audited. Although auditd takes care of enabling
this for all processes which launch after it does, adding the kernel argument
ensures it is set for every process during boot. Identifiers:
CCE-80825-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.02, DSS05.03, DSS05.04, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, CCI-001464, CCI-000130, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AC-17(1), AU-14(1), AU-10, CM-6(a), IR-5(1), DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.3, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000254-GPOS-00095, SRG-OS-000254-VMM-000880, RHEL-08-030601, 4.1.1.3, SV-230468r792904_rule Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80825-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030601
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- grub2_audit_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="audit=1"
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
tags:
- CCE-80825-3
- CJIS-5.4.1.1
- DISA-STIG-RHEL-08-030601
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- grub2_audit_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then
grubby --update-kernel=ALL --args=audit=1 --env=/boot/grub2/grubenv
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
[customizations.kernel]
append = "audit=1"
|
Extend Audit Backlog Limit for the Audit Daemon
[ref]ruleTo improve the kernel capacity to queue all log events, even those which occurred
prior to the audit daemon, add the argument audit_backlog_limit=8192 to the default
GRUB 2 command line for the Linux operating system.
To ensure that audit_backlog_limit=8192 is added as a kernel command line
argument to newly installed kernels, add audit_backlog_limit=8192 to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... audit_backlog_limit=8192 ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="audit_backlog_limit=8192" Rationale:audit_backlog_limit sets the queue length for audit events awaiting transfer
to the audit daemon. Until the audit daemon is up and running, all log messages
are stored in this queue. If the queue is overrun during boot process, the action
defined by audit failure flag is taken. Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-80943-4
- DISA-STIG-RHEL-08-030602
- NIST-800-53-CM-6(a)
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="audit_backlog_limit=8192"
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
tags:
- CCE-80943-4
- DISA-STIG-RHEL-08-030602
- NIST-800-53-CM-6(a)
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then
grubby --update-kernel=ALL --args=audit_backlog_limit=8192 --env=/boot/grub2/grubenv
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
[customizations.kernel]
append = "audit_backlog_limit=8192"
|
GRUB2 bootloader configuration
[ref]groupDuring the boot process, the boot loader is
responsible for starting the execution of the kernel and passing
options to it. The boot loader allows for the selection of
different kernels - possibly on different partitions or media.
The default Red Hat Enterprise Linux 8 boot loader for x86 systems is called GRUB2.
Options it can pass to the kernel include single-user mode, which
provides root access without any authentication, and the ability to
disable SELinux. To prevent local users from modifying the boot
parameters and endangering security, protect the boot loader configuration
with a password and ensure its configuration file's permissions
are set properly. |
contains 8 rules |
Non-UEFI GRUB2 bootloader configuration
[ref]groupNon-UEFI GRUB2 bootloader configuration |
contains 4 rules |
Verify /boot/grub2/grub.cfg Group Ownership
[ref]ruleThe file /boot/grub2/grub.cfg should
be group-owned by the root group to prevent
destruction or modification of the file.
To properly set the group owner of /boot/grub2/grub.cfg , run the command:
$ sudo chgrp root /boot/grub2/grub.cfg Rationale:The root group is a highly-privileged group. Furthermore, the group-owner of this
file should not have any access privileges anyway. Identifiers:
CCE-80800-6 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1, 1.5.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /boot/grub2/grub.cfg
stat:
path: /boot/grub2/grub.cfg
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80800-6
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_groupowner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /boot/grub2/grub.cfg
file:
path: /boot/grub2/grub.cfg
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80800-6
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_groupowner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /boot/grub2/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify /boot/grub2/grub.cfg User Ownership
[ref]ruleThe file /boot/grub2/grub.cfg should
be owned by the root user to prevent destruction
or modification of the file.
To properly set the owner of /boot/grub2/grub.cfg , run the command:
$ sudo chown root /boot/grub2/grub.cfg Rationale:Only root should be able to modify important boot parameters. Identifiers:
CCE-80805-5 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1, 1.5.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /boot/grub2/grub.cfg
stat:
path: /boot/grub2/grub.cfg
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80805-5
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_owner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /boot/grub2/grub.cfg
file:
path: /boot/grub2/grub.cfg
owner: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80805-5
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_owner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chown 0 /boot/grub2/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify /boot/grub2/grub.cfg Permissions
[ref]ruleFile permissions for /boot/grub2/grub.cfg should be set to 600.
To properly set the permissions of /boot/grub2/grub.cfg , run the command:
$ sudo chmod 600 /boot/grub2/grub.cfg Rationale:Proper permissions ensure that only the root user can modify important boot
parameters. Identifiers:
CCE-80814-7 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 1.5.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /boot/grub2/grub.cfg
stat:
path: /boot/grub2/grub.cfg
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80814-7
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /boot/grub2/grub.cfg
file:
path: /boot/grub2/grub.cfg
mode: u-xs,g-xwrs,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80814-7
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xwrs,o-xwrt /boot/grub2/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Boot Loader Password in grub2
[ref]ruleThe grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:
# grub2-setpassword
When prompted, enter the password that was selected.
Warning:
To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation
must be automated as a component of machine provisioning, or followed manually as outlined above.
Also, do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. Rationale:Password protection on the boot loader configuration ensures
users with physical access cannot trivially alter
important bootloader settings. These include which kernel to use,
and whether to enter single-user mode. Identifiers:
CCE-80828-7 References:
BP28(R17), 1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, RHEL-08-010150, 1.5.2, SV-230235r743925_rule |
UEFI GRUB2 bootloader configuration
[ref]groupUEFI GRUB2 bootloader configuration |
contains 4 rules |
Verify the UEFI Boot Loader grub.cfg Group Ownership
[ref]ruleThe file /boot/efi/EFI/redhat/grub.cfg should
be group-owned by the root group to prevent
destruction or modification of the file.
To properly set the group owner of /boot/efi/EFI/redhat/grub.cfg , run the command:
$ sudo chgrp root /boot/efi/EFI/redhat/grub.cfg Rationale:The root group is a highly-privileged group. Furthermore, the group-owner of this
file should not have any access privileges anyway. Identifiers:
CCE-85915-7 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1, 1.5.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /boot/efi/EFI/redhat/grub.cfg
stat:
path: /boot/efi/EFI/redhat/grub.cfg
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85915-7
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_groupowner_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /boot/efi/EFI/redhat/grub.cfg
file:
path: /boot/efi/EFI/redhat/grub.cfg
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85915-7
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_groupowner_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /boot/efi/EFI/redhat/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify the UEFI Boot Loader grub.cfg User Ownership
[ref]ruleThe file /boot/efi/EFI/redhat/grub.cfg should
be owned by the root user to prevent destruction
or modification of the file.
To properly set the owner of /boot/efi/EFI/redhat/grub.cfg , run the command:
$ sudo chown root /boot/efi/EFI/redhat/grub.cfg Rationale:Only root should be able to modify important boot parameters. Identifiers:
CCE-85913-2 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1, 1.5.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /boot/efi/EFI/redhat/grub.cfg
stat:
path: /boot/efi/EFI/redhat/grub.cfg
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85913-2
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_owner_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /boot/efi/EFI/redhat/grub.cfg
file:
path: /boot/efi/EFI/redhat/grub.cfg
owner: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85913-2
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- configure_strategy
- file_owner_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chown 0 /boot/efi/EFI/redhat/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify the UEFI Boot Loader grub.cfg Permissions
[ref]ruleFile permissions for /boot/efi/EFI/redhat/grub.cfg should be set to 700.
To properly set the permissions of /boot/efi/EFI/redhat/grub.cfg , run the command:
$ sudo chmod 700 /boot/efi/EFI/redhat/grub.cfg Rationale:Proper permissions ensure that only the root user can modify important boot
parameters. Identifiers:
CCE-85912-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 1.5.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /boot/efi/EFI/redhat/grub.cfg
stat:
path: /boot/efi/EFI/redhat/grub.cfg
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85912-4
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-s,g-xwrs,o-xwrt on /boot/efi/EFI/redhat/grub.cfg
file:
path: /boot/efi/EFI/redhat/grub.cfg
mode: u-s,g-xwrs,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85912-4
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_efi_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-s,g-xwrs,o-xwrt /boot/efi/EFI/redhat/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set the UEFI Boot Loader Password
[ref]ruleThe grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:
# grub2-setpassword
When prompted, enter the password that was selected.
Warning:
To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation
must be automated as a component of machine provisioning, or followed manually as outlined above.
Also, do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. Rationale:Password protection on the boot loader configuration ensures
users with physical access cannot trivially alter
important bootloader settings. These include which kernel to use,
and whether to enter single-user mode. Identifiers:
CCE-80829-5 References:
BP28(R17), 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, RHEL-08-010140, 1.5.2, SV-230234r743922_rule |
Configure Syslog
[ref]groupThe syslog service has been the default Unix logging mechanism for
many years. It has a number of downsides, including inconsistent log format,
lack of authentication for received messages, and lack of authentication,
encryption, or reliable transport for messages sent over a network. However,
due to its long history, syslog is a de facto standard which is supported by
almost all Unix applications.
In Red Hat Enterprise Linux 8, rsyslog has replaced ksyslogd as the
syslog daemon of choice, and it includes some additional security features
such as reliable, connection-oriented (i.e. TCP) transmission of logs, the
option to log to database formats, and the encryption of log data en route to
a central logging server.
This section discusses how to configure rsyslog for
best effect, and how to use tools provided with the system to maintain and
monitor logs. |
contains 6 rules |
systemd-journald
[ref]groupsystemd-journald is a system service that collects and stores
logging data. It creates and maintains structured, indexed
journals based on logging information that is received from a
variety of sources.
For more information on systemd-journald and additional systemd-journald configuration options, see
https://systemd.io/. |
contains 3 rules |
Ensure journald is configured to compress large log files
[ref]ruleThe journald system can compress large log files to avoid fill the system disk. Rationale:Log files that are not properly compressed run the risk of growing so large that they fill up the log partition. Valuable logging information could be lost if the log partition becomes full. Identifiers:
CCE-85930-6 References:
4.2.2.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Setting shell-quoted shell-style assignment of 'Compress' to 'yes' in '/etc/systemd/journald.conf'
block:
- name: Check for duplicate values
lineinfile:
path: /etc/systemd/journald.conf
create: false
regexp: ^\s*Compress=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/systemd/journald.conf
lineinfile:
path: /etc/systemd/journald.conf
create: false
regexp: ^\s*Compress=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/systemd/journald.conf
lineinfile:
path: /etc/systemd/journald.conf
create: true
regexp: ^\s*Compress=
line: Compress="yes"
state: present
insertbefore: ^# Compress
validate: /usr/bin/bash -n %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85930-6
- journald_compress
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/systemd/journald.conf" ] ; then
LC_ALL=C sed -i "/^\s*Compress=/d" "/etc/systemd/journald.conf"
else
touch "/etc/systemd/journald.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/journald.conf"
cp "/etc/systemd/journald.conf" "/etc/systemd/journald.conf.bak"
# Insert before the line matching the regex '^#\s*Compress'.
line_number="$(LC_ALL=C grep -n "^#\s*Compress" "/etc/systemd/journald.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^#\s*Compress', insert at
# the end of the file.
printf '%s\n' "Compress='yes'" >> "/etc/systemd/journald.conf"
else
head -n "$(( line_number - 1 ))" "/etc/systemd/journald.conf.bak" > "/etc/systemd/journald.conf"
printf '%s\n' "Compress='yes'" >> "/etc/systemd/journald.conf"
tail -n "+$(( line_number ))" "/etc/systemd/journald.conf.bak" >> "/etc/systemd/journald.conf"
fi
# Clean up after ourselves.
rm "/etc/systemd/journald.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure journald is configured to send logs to rsyslog
[ref]ruleData from journald may be stored in volatile memory or persisted locally.
Utilities exist to accept remote export of journald logs. Rationale:Storing log data on a remote host protects log integrity from local attacks. If an attacker gains root access on the local system, they could tamper with or remove log data that is stored on the local system. Identifiers:
CCE-85995-9 References:
4.2.2.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Setting shell-quoted shell-style assignment of 'ForwardToSyslog' to 'yes'
in '/etc/systemd/journald.conf'
block:
- name: Check for duplicate values
lineinfile:
path: /etc/systemd/journald.conf
create: false
regexp: ^\s*ForwardToSyslog=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/systemd/journald.conf
lineinfile:
path: /etc/systemd/journald.conf
create: false
regexp: ^\s*ForwardToSyslog=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/systemd/journald.conf
lineinfile:
path: /etc/systemd/journald.conf
create: true
regexp: ^\s*ForwardToSyslog=
line: ForwardToSyslog="yes"
state: present
insertbefore: ^# ForwardToSyslog
validate: /usr/bin/bash -n %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85995-9
- journald_forward_to_syslog
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/systemd/journald.conf" ] ; then
LC_ALL=C sed -i "/^\s*ForwardToSyslog=/d" "/etc/systemd/journald.conf"
else
touch "/etc/systemd/journald.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/journald.conf"
cp "/etc/systemd/journald.conf" "/etc/systemd/journald.conf.bak"
# Insert before the line matching the regex '^#\s*ForwardToSyslog'.
line_number="$(LC_ALL=C grep -n "^#\s*ForwardToSyslog" "/etc/systemd/journald.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^#\s*ForwardToSyslog', insert at
# the end of the file.
printf '%s\n' "ForwardToSyslog='yes'" >> "/etc/systemd/journald.conf"
else
head -n "$(( line_number - 1 ))" "/etc/systemd/journald.conf.bak" > "/etc/systemd/journald.conf"
printf '%s\n' "ForwardToSyslog='yes'" >> "/etc/systemd/journald.conf"
tail -n "+$(( line_number ))" "/etc/systemd/journald.conf.bak" >> "/etc/systemd/journald.conf"
fi
# Clean up after ourselves.
rm "/etc/systemd/journald.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure journald is configured to write log files to persistent disk
[ref]ruleThe journald system may store log files in volatile memory or locally on disk.
If the logs are only stored in volatile memory they will we lost upon reboot. Rationale:Log files contain valuable data and need to be persistent to aid in possible investigations. Identifiers:
CCE-86045-2 References:
4.2.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Setting shell-quoted shell-style assignment of 'Storage' to 'persistent' in
'/etc/systemd/journald.conf'
block:
- name: Check for duplicate values
lineinfile:
path: /etc/systemd/journald.conf
create: false
regexp: ^\s*Storage=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/systemd/journald.conf
lineinfile:
path: /etc/systemd/journald.conf
create: false
regexp: ^\s*Storage=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/systemd/journald.conf
lineinfile:
path: /etc/systemd/journald.conf
create: true
regexp: ^\s*Storage=
line: Storage="persistent"
state: present
insertbefore: ^# Storage
validate: /usr/bin/bash -n %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86045-2
- journald_storage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/systemd/journald.conf" ] ; then
LC_ALL=C sed -i "/^\s*Storage=/d" "/etc/systemd/journald.conf"
else
touch "/etc/systemd/journald.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/journald.conf"
cp "/etc/systemd/journald.conf" "/etc/systemd/journald.conf.bak"
# Insert before the line matching the regex '^#\s*Storage'.
line_number="$(LC_ALL=C grep -n "^#\s*Storage" "/etc/systemd/journald.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^#\s*Storage', insert at
# the end of the file.
printf '%s\n' "Storage='persistent'" >> "/etc/systemd/journald.conf"
else
head -n "$(( line_number - 1 ))" "/etc/systemd/journald.conf.bak" > "/etc/systemd/journald.conf"
printf '%s\n' "Storage='persistent'" >> "/etc/systemd/journald.conf"
tail -n "+$(( line_number ))" "/etc/systemd/journald.conf.bak" >> "/etc/systemd/journald.conf"
fi
# Clean up after ourselves.
rm "/etc/systemd/journald.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Rsyslog Logs Sent To Remote Host
[ref]groupIf system logs are to be useful in detecting malicious
activities, it is necessary to send logs to a remote server. An
intruder who has compromised the root account on a system may
delete the log entries which indicate that the system was attacked
before they are seen by an administrator.
However, it is recommended that logs be stored on the local
host in addition to being sent to the loghost, especially if
rsyslog has been configured to use the UDP protocol to send
messages over a network. UDP does not guarantee reliable delivery,
and moderately busy sites will lose log messages occasionally,
especially in periods of high traffic which may be the result of an
attack. In addition, remote rsyslog messages are not
authenticated in any way by default, so it is easy for an attacker to
introduce spurious messages to the central log server. Also, some
problems cause loss of network connectivity, which will prevent the
sending of messages to the central server. For all of these reasons, it is
better to store log messages both centrally and on each host, so
that they can be correlated if necessary. |
contains 1 rule |
Ensure Logs Sent To Remote Host
[ref]ruleTo configure rsyslog to send logs to a remote log server,
open /etc/rsyslog.conf and read and understand the last section of the file,
which describes the multiple directives necessary to activate remote
logging.
Along with these other directives, the system can be configured
to forward its logs to a particular log server by
adding or correcting one of the following lines,
substituting logcollector appropriately.
The choice of protocol depends on the environment of the system;
although TCP and RELP provide more reliable message delivery,
they may not be supported in all environments.
To use UDP for log message delivery:
*.* @logcollector
To use TCP for log message delivery:
*.* @@logcollector
To use RELP for log message delivery:
*.* :omrelp:logcollector
There must be a resolvable DNS CNAME or Alias record set to "logcollector" for logs to be sent correctly to the centralized logging utility.Rationale:A log server (loghost) receives syslog messages from one or more
systems. This data can be used as an additional log source in the event a
system is compromised and its local logs are suspect. Forwarding log messages
to a remote loghost also provides system administrators with a centralized
place to view the status of multiple hosts within the enterprise. Identifiers:
CCE-80863-4 References:
BP28(R7), NT28(R43), NT12(R5), 1, 13, 14, 15, 16, 2, 3, 5, 6, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.04, DSS05.07, MEA02.01, CCI-000366, CCI-001348, CCI-000136, CCI-001851, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 7.1, SR 7.2, 0988, 1405, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.17.2.1, CIP-003-8 R5.2, CIP-004-6 R3.3, CM-6(a), AU-4(1), AU-9(2), PR.DS-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000479-GPOS-00224, SRG-OS-000480-GPOS-00227, SRG-OS-000342-GPOS-00133, SRG-OS-000032-VMM-000130, RHEL-08-030690, 4.2.1.5, SV-230479r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value rsyslog_remote_loghost_address # promote to variable
set_fact:
rsyslog_remote_loghost_address: !!str logcollector
tags:
- always
- name: Set rsyslog remote loghost
lineinfile:
dest: /etc/rsyslog.conf
regexp: ^\*\.\*
line: '*.* @@{{ rsyslog_remote_loghost_address }}'
create: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80863-4
- DISA-STIG-RHEL-08-030690
- NIST-800-53-AU-4(1)
- NIST-800-53-AU-9(2)
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- rsyslog_remote_loghost
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
rsyslog_remote_loghost_address='logcollector'
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/rsyslog.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^\*\.\*")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "@@$rsyslog_remote_loghost_address"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^\*\.\*\\>" "/etc/rsyslog.conf"; then
"${sed_command[@]}" "s/^\*\.\*\\>.*/$formatted_output/gi" "/etc/rsyslog.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80863-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/rsyslog.conf" >> "/etc/rsyslog.conf"
printf '%s\n' "$formatted_output" >> "/etc/rsyslog.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure rsyslog is Installed
[ref]ruleRsyslog is installed by default. The rsyslog package can be installed with the following command: $ sudo yum install rsyslog Rationale:The rsyslog package provides the rsyslog daemon, which provides
system logging services. Identifiers:
CCE-80847-7 References:
BP28(R5), NT28(R46), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-001311, CCI-001312, CCI-000366, 164.312(a)(2)(ii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), PR.PT-1, FTP_ITC_EXT.1.1, SRG-OS-000479-GPOS-00224, SRG-OS-000051-GPOS-00024, SRG-OS-000480-GPOS-00227, RHEL-08-030670, 4.2.1.1, SV-230477r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure rsyslog is installed
package:
name: rsyslog
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80847-7
- DISA-STIG-RHEL-08-030670
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_rsyslog_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "rsyslog" ; then
yum install -y "rsyslog"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
package --add=rsyslog
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_rsyslog
class install_rsyslog {
package { 'rsyslog':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "rsyslog"
version = "*"
|
Enable rsyslog Service
[ref]ruleThe rsyslog service provides syslog-style logging by default on Red Hat Enterprise Linux 8.
The rsyslog service can be enabled with the following command:
$ sudo systemctl enable rsyslog.service Rationale:The rsyslog service must be running in order to provide
logging services, which are essential to system administration. Identifiers:
CCE-80886-5 References:
BP28(R5), NT28(R46), 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, CCI-001311, CCI-001312, CCI-001557, CCI-001851, CCI-000366, 164.312(a)(2)(ii), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, A.17.2.1, CM-6(a), AU-4(1), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.DS-4, PR.PT-1, SRG-OS-000480-GPOS-00227, RHEL-08-010561, 4.2.1.2, SV-230298r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Enable service rsyslog
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service rsyslog
service:
name: rsyslog
enabled: 'yes'
state: started
masked: 'no'
when:
- '"rsyslog" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80886-5
- DISA-STIG-RHEL-08-010561
- NIST-800-53-AU-4(1)
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_rsyslog_enabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'rsyslog.service'
"$SYSTEMCTL_EXEC" start 'rsyslog.service'
"$SYSTEMCTL_EXEC" enable 'rsyslog.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include enable_rsyslog
class enable_rsyslog {
service {'rsyslog':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["rsyslog"]
|
Network Configuration and Firewalls
[ref]groupMost systems must be connected to a network of some
sort, and this brings with it the substantial risk of network
attack. This section discusses the security impact of decisions
about networking which must be made when configuring a system.
This section also discusses firewalls, network access
controls, and other network security frameworks, which allow
system-level rules to be written that can limit an attackers' ability
to connect to your system. These rules can specify that network
traffic should be allowed or denied from certain IP addresses,
hosts, and networks. The rules can also specify which of the
system's network services are available to particular hosts or
networks. |
contains 31 rules |
firewalld
[ref]groupThe dynamic firewall daemon firewalld provides a
dynamically managed firewall with support for network “zones” to assign
a level of trust to a network and its associated connections and interfaces.
It has support for IPv4 and IPv6 firewall settings. It supports Ethernet
bridges and has a separation of runtime and permanent configuration options.
It also has an interface for services or applications to add firewall rules
directly.
A graphical configuration tool, firewall-config , is used to configure
firewalld , which in turn uses iptables tool to communicate
with Netfilter in the kernel which implements packet filtering.
The firewall service provided by firewalld is dynamic rather than
static because changes to the configuration can be made at anytime and are
immediately implemented. There is no need to save or apply the changes. No
unintended disruption of existing network connections occurs as no part of
the firewall has to be reloaded. |
contains 3 rules |
Inspect and Activate Default firewalld Rules
[ref]groupFirewalls can be used to separate networks into different zones
based on the level of trust the user has decided to place on the devices and
traffic within that network. NetworkManager informs firewalld to which
zone an interface belongs. An interface's assigned zone can be changed by
NetworkManager or via the firewall-config tool.
The zone settings in /etc/firewalld/ are a range of preset settings
which can be quickly applied to a network interface. These are the zones
provided by firewalld sorted according to the default trust level of the
zones from untrusted to trusted:
drop
Any incoming network packets are dropped, there is no
reply. Only outgoing network connections are possible. block
Any incoming network connections are rejected with an
icmp-host-prohibited message for IPv4 and icmp6-adm-prohibited
for IPv6. Only network connections initiated from within the system are
possible. public
For use in public areas. You do not trust the other
computers on the network to not harm your computer. Only selected incoming
connections are accepted. external
For use on external networks with masquerading enabled
especially for routers. You do not trust the other computers on the network to
not harm your computer. Only selected incoming connections are accepted. dmz
For computers in your demilitarized zone that are
publicly-accessible with limited access to your internal network. Only selected
incoming connections are accepted. work
For use in work areas. You mostly trust the other computers
on networks to not harm your computer. Only selected incoming connections are
accepted. home
For use in home areas. You mostly trust the other computers
on networks to not harm your computer. Only selected incoming connections are
accepted. internal
For use on internal networks. You mostly trust the
other computers on the networks to not harm your computer. Only selected
incoming connections are accepted. trusted
All network connections are accepted.
It is possible to designate one of these zones to be the default zone. When
interface connections are added to NetworkManager , they are assigned
to the default zone. On installation, the default zone in firewalld is set to
be the public zone.
To find out all the settings of a zone, for example the public zone,
enter the following command as root:
# firewall-cmd --zone=public --list-all
Example output of this command might look like the following:
# firewall-cmd --zone=public --list-all
public
interfaces:
services: mdns dhcpv6-client ssh
ports:
forward-ports:
icmp-blocks: source-quench
To view the network zones currently active, enter the following command as root:
# firewall-cmd --get-service
The following listing displays the result of this command
on common Red Hat Enterprise Linux 8 system:
# firewall-cmd --get-service
amanda-client bacula bacula-client dhcp dhcpv6 dhcpv6-client dns ftp
high-availability http https imaps ipp ipp-client ipsec kerberos kpasswd
ldap ldaps libvirt libvirt-tls mdns mountd ms-wbt mysql nfs ntp openvpn
pmcd pmproxy pmwebapi pmwebapis pop3s postgresql proxy-dhcp radius rpc-bind
samba samba-client smtp ssh telnet tftp tftp-client transmission-client
vnc-server wbem-https
Finally to view the network zones that will be active after the next firewalld
service reload, enter the following command as root:
# firewall-cmd --get-service --permanent |
contains 2 rules |
Install firewalld Package
[ref]ruleThe firewalld package can be installed with the following command:
$ sudo yum install firewalld Rationale:"Firewalld" provides an easy and effective way to block/limit remote access to the system via ports, services, and protocols.
Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best.
Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless.
Red Hat Enterprise Linux 8 functionality (e.g., SSH) must be capable of taking enforcement action if the audit reveals unauthorized activity.
Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets)." Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure firewalld is installed
package:
name: firewalld
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82998-6
- DISA-STIG-RHEL-08-040100
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_firewalld_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "firewalld" ; then
yum install -y "firewalld"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
package --add=firewalld
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_firewalld
class install_firewalld {
package { 'firewalld':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "firewalld"
version = "*"
|
Verify firewalld Enabled
[ref]rule
The firewalld service can be enabled with the following command:
$ sudo systemctl enable firewalld.service Rationale:Access control methods provide the ability to enhance system security posture
by restricting services and known good IP addresses and address ranges. This
prevents connections from unknown hosts and protocols. Identifiers:
CCE-80877-4 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.3, 3.4.7, CCI-000366, CCI-000382, CCI-002314, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CIP-003-8 R4, CIP-003-8 R5, CIP-004-6 R3, AC-4, CM-7(b), CA-3(5), SC-7(21), CM-6(a), PR.IP-1, FMT_MOF_EXT.1, SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232, RHEL-08-040101, 3.4.2.1, SV-244544r743881_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Enable service firewalld
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service firewalld
service:
name: firewalld
enabled: 'yes'
state: started
masked: 'no'
when:
- '"firewalld" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80877-4
- DISA-STIG-RHEL-08-040101
- NIST-800-171-3.1.3
- NIST-800-171-3.4.7
- NIST-800-53-AC-4
- NIST-800-53-CA-3(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(21)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_firewalld_enabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'firewalld.service'
"$SYSTEMCTL_EXEC" start 'firewalld.service'
"$SYSTEMCTL_EXEC" enable 'firewalld.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include enable_firewalld
class enable_firewalld {
service {'firewalld':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["firewalld"]
|
Strengthen the Default Ruleset
[ref]groupThe default rules can be strengthened. The system
scripts that activate the firewall rules expect them to be defined
in configuration files under the /etc/firewalld/services
and /etc/firewalld/zones directories.
The following recommendations describe how to strengthen the
default ruleset configuration file. An alternative to editing this
configuration file is to create a shell script that makes calls to
the firewall-cmd program to load in rules under the /etc/firewalld/services
and /etc/firewalld/zones directories.
Instructions apply to both unless otherwise noted. Language and address
conventions for regular firewalld rules are used throughout this section. Warning:
The program firewall-config
allows additional services to penetrate the default firewall rules
and automatically adjusts the firewalld ruleset(s). |
contains 1 rule |
Set Default firewalld Zone for Incoming Packets
[ref]ruleTo set the default zone to drop for
the built-in default zone which processes incoming IPv4 and IPv6 packets,
modify the following line in
/etc/firewalld/firewalld.conf to be:
DefaultZone=drop Warning:
To prevent denying any access to the system, automatic remediation
of this control is not available. Remediation must be automated as
a component of machine provisioning, or followed manually as outlined
above. Rationale:In firewalld the default zone is applied only after all
the applicable rules in the table are examined for a match. Setting the
default zone to drop implements proper design for a firewall, i.e.
any packets which are not explicitly permitted should not be
accepted. Identifiers:
CCE-80890-7 References:
11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.3, 3.4.7, 3.13.6, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, 1416, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CA-3(5), CM-7(b), SC-7(23), CM-6(a), PR.IP-1, PR.PT-3, FMT_MOF_EXT.1, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000, 3.4.2.4 |
The system includes support for Internet Protocol
version 6. A major and often-mentioned improvement over IPv4 is its
enormous increase in the number of available addresses. Another
important feature is its support for automatic configuration of
many network settings. |
contains 7 rules |
Configure IPv6 Settings if Necessary
[ref]groupA major feature of IPv6 is the extent to which systems
implementing it can automatically configure their networking
devices using information from the network. From a security
perspective, manually configuring important configuration
information is preferable to accepting it from the network
in an unauthenticated fashion. |
contains 7 rules |
Configure Accepting Router Advertisements on All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_ra kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_ra=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_ra = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. Identifiers:
CCE-81006-9 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, RHEL-08-040261, 3.2.9, SV-230541r818875_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.accept_ra.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81006-9
- DISA-STIG-RHEL-08-040261
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra
- name: Comment out any occurrences of net.ipv6.conf.all.accept_ra from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.accept_ra
replace: '#net.ipv6.conf.all.accept_ra'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81006-9
- DISA-STIG-RHEL-08-040261
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_ra_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_ra_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_ra is set
sysctl:
name: net.ipv6.conf.all.accept_ra
value: '{{ sysctl_net_ipv6_conf_all_accept_ra_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81006-9
- DISA-STIG-RHEL-08-040261
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv6.conf.all.accept_ra from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_ra.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv6.conf.all.accept_ra" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv6_conf_all_accept_ra_value='0'
#
# Set runtime for net.ipv6.conf.all.accept_ra
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.accept_ra="$sysctl_net_ipv6_conf_all_accept_ra_value"
#
# If net.ipv6.conf.all.accept_ra present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.accept_ra = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_ra")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_ra_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_ra\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv6.conf.all.accept_ra\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81006-9"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv6.conf.all.accept_ra%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_all_accept_ra.conf
overwrite: true
|
Disable Accepting ICMP Redirects for All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_redirects = 0 Rationale:An illicit ICMP redirect message could result in a man-in-the-middle attack. Identifiers:
CCE-81009-3 References:
BP28(R22), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, RHEL-08-040280, 3.2.2, SV-230544r818887_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81009-3
- DISA-STIG-RHEL-08-040280
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_redirects
- name: Comment out any occurrences of net.ipv6.conf.all.accept_redirects from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.accept_redirects
replace: '#net.ipv6.conf.all.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81009-3
- DISA-STIG-RHEL-08-040280
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_redirects
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_redirects is set
sysctl:
name: net.ipv6.conf.all.accept_redirects
value: '{{ sysctl_net_ipv6_conf_all_accept_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81009-3
- DISA-STIG-RHEL-08-040280
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv6.conf.all.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv6.conf.all.accept_redirects" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv6_conf_all_accept_redirects_value='0'
#
# Set runtime for net.ipv6.conf.all.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.accept_redirects="$sysctl_net_ipv6_conf_all_accept_redirects_value"
#
# If net.ipv6.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.accept_redirects = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_redirects_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_redirects\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv6.conf.all.accept_redirects\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81009-3"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv6.conf.all.accept_redirects%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_all_accept_redirects.conf
overwrite: true
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router, which can
be used to bypass network security measures. This requirement applies only to the
forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and
the system is functioning as a router.
Accepting source-routed packets in the IPv6 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. Identifiers:
CCE-81013-5 References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040240, 3.2.1, SV-230538r818860_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81013-5
- DISA-STIG-RHEL-08-040240
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_source_route
- name: Comment out any occurrences of net.ipv6.conf.all.accept_source_route from
/etc/sysctl.d/*.conf files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.accept_source_route
replace: '#net.ipv6.conf.all.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81013-5
- DISA-STIG-RHEL-08-040240
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_source_route
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_source_route is set
sysctl:
name: net.ipv6.conf.all.accept_source_route
value: '{{ sysctl_net_ipv6_conf_all_accept_source_route_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81013-5
- DISA-STIG-RHEL-08-040240
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_source_route
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv6.conf.all.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv6.conf.all.accept_source_route" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv6_conf_all_accept_source_route_value='0'
#
# Set runtime for net.ipv6.conf.all.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.accept_source_route="$sysctl_net_ipv6_conf_all_accept_source_route_value"
#
# If net.ipv6.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.accept_source_route = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_source_route_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_source_route\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv6.conf.all.accept_source_route\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81013-5"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv6.conf.all.accept_source_route%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_all_accept_source_route.conf
overwrite: true
|
Disable Kernel Parameter for IPv6 Forwarding
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.forwarding kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.forwarding=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.forwarding = 0 Rationale:IP forwarding permits the kernel to forward packets from one network
interface to another. The ability to forward packets between two networks is
only appropriate for systems acting as routers. Identifiers:
CCE-82863-2 References:
1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, 3.1.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.forwarding.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82863-2
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_forwarding
- name: Comment out any occurrences of net.ipv6.conf.all.forwarding from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.forwarding
replace: '#net.ipv6.conf.all.forwarding'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82863-2
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_forwarding
- name: XCCDF Value sysctl_net_ipv6_conf_all_forwarding_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_forwarding_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.forwarding is set
sysctl:
name: net.ipv6.conf.all.forwarding
value: '{{ sysctl_net_ipv6_conf_all_forwarding_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82863-2
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_forwarding
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv6.conf.all.forwarding from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.forwarding.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv6.conf.all.forwarding" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv6_conf_all_forwarding_value='0'
#
# Set runtime for net.ipv6.conf.all.forwarding
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.forwarding="$sysctl_net_ipv6_conf_all_forwarding_value"
#
# If net.ipv6.conf.all.forwarding present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.forwarding = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.forwarding")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_forwarding_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.forwarding\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv6.conf.all.forwarding\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-82863-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Accepting Router Advertisements on all IPv6 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_ra kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_ra=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_ra = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. Identifiers:
CCE-81007-7 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, RHEL-08-040262, 3.2.9, SV-230542r818878_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_ra.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81007-7
- DISA-STIG-RHEL-08-040262
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra
- name: Comment out any occurrences of net.ipv6.conf.default.accept_ra from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_ra
replace: '#net.ipv6.conf.default.accept_ra'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81007-7
- DISA-STIG-RHEL-08-040262
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_ra_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_ra_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_ra is set
sysctl:
name: net.ipv6.conf.default.accept_ra
value: '{{ sysctl_net_ipv6_conf_default_accept_ra_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81007-7
- DISA-STIG-RHEL-08-040262
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv6.conf.default.accept_ra from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_ra.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv6.conf.default.accept_ra" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv6_conf_default_accept_ra_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_ra
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_ra="$sysctl_net_ipv6_conf_default_accept_ra_value"
#
# If net.ipv6.conf.default.accept_ra present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_ra = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_ra")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_ra_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_ra\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv6.conf.default.accept_ra\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81007-7"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv6.conf.default.accept_ra%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_default_accept_ra.conf
overwrite: true
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_redirects = 0 Rationale:An illicit ICMP redirect message could result in a man-in-the-middle attack. Identifiers:
CCE-81010-1 References:
BP28(R22), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, RHEL-08-040210, 3.2.2, SV-230535r818848_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81010-1
- DISA-STIG-RHEL-08-040210
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_redirects
- name: Comment out any occurrences of net.ipv6.conf.default.accept_redirects from
/etc/sysctl.d/*.conf files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_redirects
replace: '#net.ipv6.conf.default.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81010-1
- DISA-STIG-RHEL-08-040210
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_redirects
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_redirects is set
sysctl:
name: net.ipv6.conf.default.accept_redirects
value: '{{ sysctl_net_ipv6_conf_default_accept_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81010-1
- DISA-STIG-RHEL-08-040210
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv6.conf.default.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv6.conf.default.accept_redirects" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv6_conf_default_accept_redirects_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_redirects="$sysctl_net_ipv6_conf_default_accept_redirects_value"
#
# If net.ipv6.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_redirects = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_redirects_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_redirects\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv6.conf.default.accept_redirects\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81010-1"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv6.conf.default.accept_redirects%20%3D%200%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_default_accept_redirects.conf
overwrite: true
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router, which can
be used to bypass network security measures. This requirement applies only to the
forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and
the system is functioning as a router.
Accepting source-routed packets in the IPv6 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. Identifiers:
CCE-81015-0 References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040250, 3.2.1, SV-230539r818866_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81015-0
- DISA-STIG-RHEL-08-040250
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
- name: Comment out any occurrences of net.ipv6.conf.default.accept_source_route from
/etc/sysctl.d/*.conf files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_source_route
replace: '#net.ipv6.conf.default.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81015-0
- DISA-STIG-RHEL-08-040250
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_source_route is set
sysctl:
name: net.ipv6.conf.default.accept_source_route
value: '{{ sysctl_net_ipv6_conf_default_accept_source_route_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81015-0
- DISA-STIG-RHEL-08-040250
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv6.conf.default.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv6.conf.default.accept_source_route" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv6_conf_default_accept_source_route_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_source_route="$sysctl_net_ipv6_conf_default_accept_source_route_value"
#
# If net.ipv6.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_source_route = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_source_route_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_source_route\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv6.conf.default.accept_source_route\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81015-0"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv6.conf.default.accept_source_route%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_default_accept_source_route.conf
overwrite: true
|
Kernel Parameters Which Affect Networking
[ref]groupThe sysctl utility is used to set
parameters which affect the operation of the Linux kernel. Kernel parameters
which affect networking and have security implications are described here. |
contains 16 rules |
Network Related Kernel Runtime Parameters for Hosts and Routers
[ref]groupCertain kernel parameters should be set for systems which are
acting as either hosts or routers to improve the system's ability defend
against certain types of IPv4 protocol attacks. |
contains 13 rules |
Disable Accepting ICMP Redirects for All IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.accept_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be
disabled unless absolutely required." Identifiers:
CCE-80917-8 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, 5.10.1.1, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000366, CCI-001503, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, RHEL-08-040279, 3.2.2, SV-244553r818884_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80917-8
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040279
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.accept_redirects from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.accept_redirects
replace: '#net.ipv4.conf.all.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80917-8
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040279
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_all_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.accept_redirects is set
sysctl:
name: net.ipv4.conf.all.accept_redirects
value: '{{ sysctl_net_ipv4_conf_all_accept_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80917-8
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040279
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.all.accept_redirects" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_all_accept_redirects_value='0'
#
# Set runtime for net.ipv4.conf.all.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_redirects="$sysctl_net_ipv4_conf_all_accept_redirects_value"
#
# If net.ipv4.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.accept_redirects = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_accept_redirects_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.accept_redirects\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.all.accept_redirects\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80917-8"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.all.accept_redirects%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_accept_redirects.conf
overwrite: true
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router,
which can be used to bypass network security measures. This requirement
applies only to the forwarding of source-routerd traffic, such as when IPv4
forwarding is enabled and the system is functioning as a router.
Accepting source-routed packets in the IPv4 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. Identifiers:
CCE-81011-9 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040239, 3.2.1, SV-244551r818857_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81011-9
- DISA-STIG-RHEL-08-040239
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_source_route
- name: Comment out any occurrences of net.ipv4.conf.all.accept_source_route from
/etc/sysctl.d/*.conf files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.accept_source_route
replace: '#net.ipv4.conf.all.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81011-9
- DISA-STIG-RHEL-08-040239
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_source_route
- name: XCCDF Value sysctl_net_ipv4_conf_all_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.accept_source_route is set
sysctl:
name: net.ipv4.conf.all.accept_source_route
value: '{{ sysctl_net_ipv4_conf_all_accept_source_route_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81011-9
- DISA-STIG-RHEL-08-040239
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_source_route
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.all.accept_source_route" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_all_accept_source_route_value='0'
#
# Set runtime for net.ipv4.conf.all.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_source_route="$sysctl_net_ipv4_conf_all_accept_source_route_value"
#
# If net.ipv4.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.accept_source_route = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_accept_source_route_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.accept_source_route\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.all.accept_source_route\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81011-9"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.all.accept_source_route%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_accept_source_route.conf
overwrite: true
|
Enable Kernel Parameter to Log Martian Packets on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.log_martians kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.log_martians=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.log_martians = 1 Rationale:The presence of "martian" packets (which have impossible addresses)
as well as spoofed packets, source-routed packets, and redirects could be a
sign of nefarious network activity. Logging these packets enables this activity
to be detected. Identifiers:
CCE-81018-4 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.04, DSS03.05, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000126, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.11.2.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), SC-5(3)(a), DE.CM-1, PR.AC-3, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, 3.2.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.log_martians.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81018-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_conf_all_log_martians
- unknown_severity
- name: Comment out any occurrences of net.ipv4.conf.all.log_martians from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.log_martians
replace: '#net.ipv4.conf.all.log_martians'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81018-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_conf_all_log_martians
- unknown_severity
- name: XCCDF Value sysctl_net_ipv4_conf_all_log_martians_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_log_martians_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.log_martians is set
sysctl:
name: net.ipv4.conf.all.log_martians
value: '{{ sysctl_net_ipv4_conf_all_log_martians_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81018-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_conf_all_log_martians
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.log_martians from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.log_martians.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.all.log_martians" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_all_log_martians_value='1'
#
# Set runtime for net.ipv4.conf.all.log_martians
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.log_martians="$sysctl_net_ipv4_conf_all_log_martians_value"
#
# If net.ipv4.conf.all.log_martians present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.log_martians = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.log_martians")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_log_martians_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.log_martians\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.all.log_martians\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81018-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.all.log_martians%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_log_martians.conf
overwrite: true
|
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.rp_filter = 1 Rationale:Enabling reverse path filtering drops packets with source addresses
that should not have been able to be received on the interface they were
received on. It should not be used on systems which are routers for
complicated networks, but is helpful for end hosts and routers serving small
networks. Identifiers:
CCE-81021-8 References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040285, 3.2.7, SV-230549r818902_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.rp_filter.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81021-8
- DISA-STIG-RHEL-08-040285
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
- name: Comment out any occurrences of net.ipv4.conf.all.rp_filter from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.rp_filter
replace: '#net.ipv4.conf.all.rp_filter'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81021-8
- DISA-STIG-RHEL-08-040285
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
- name: XCCDF Value sysctl_net_ipv4_conf_all_rp_filter_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_rp_filter_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.rp_filter is set
sysctl:
name: net.ipv4.conf.all.rp_filter
value: '{{ sysctl_net_ipv4_conf_all_rp_filter_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81021-8
- DISA-STIG-RHEL-08-040285
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.rp_filter from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.rp_filter.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.all.rp_filter" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_all_rp_filter_value='1'
#
# Set runtime for net.ipv4.conf.all.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.rp_filter="$sysctl_net_ipv4_conf_all_rp_filter_value"
#
# If net.ipv4.conf.all.rp_filter present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.rp_filter = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.rp_filter")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_rp_filter_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.rp_filter\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.all.rp_filter\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81021-8"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.all.rp_filter%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_rp_filter.conf
overwrite: true
|
Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.secure_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.secure_redirects = 0 Rationale:Accepting "secure" ICMP redirects (from those gateways listed as
default gateways) has few legitimate uses. It should be disabled unless it is
absolutely required. Identifiers:
CCE-81016-8 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-001503, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, 3.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.secure_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81016-8
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.secure_redirects from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.secure_redirects
replace: '#net.ipv4.conf.all.secure_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81016-8
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_all_secure_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_secure_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.secure_redirects is set
sysctl:
name: net.ipv4.conf.all.secure_redirects
value: '{{ sysctl_net_ipv4_conf_all_secure_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81016-8
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.secure_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.secure_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.all.secure_redirects" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_all_secure_redirects_value='0'
#
# Set runtime for net.ipv4.conf.all.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.secure_redirects="$sysctl_net_ipv4_conf_all_secure_redirects_value"
#
# If net.ipv4.conf.all.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.secure_redirects = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.secure_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_secure_redirects_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.secure_redirects\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.all.secure_redirects\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81016-8"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.all.secure_redirects%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_secure_redirects.conf
overwrite: true
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.accept_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should
be disabled unless absolutely required. Identifiers:
CCE-80919-4 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040209, 3.2.2, SV-244550r818845_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80919-4
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040209
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.accept_redirects from
/etc/sysctl.d/*.conf files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.accept_redirects
replace: '#net.ipv4.conf.default.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80919-4
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040209
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.accept_redirects is set
sysctl:
name: net.ipv4.conf.default.accept_redirects
value: '{{ sysctl_net_ipv4_conf_default_accept_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80919-4
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040209
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.default.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.default.accept_redirects" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_default_accept_redirects_value='0'
#
# Set runtime for net.ipv4.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_redirects="$sysctl_net_ipv4_conf_default_accept_redirects_value"
#
# If net.ipv4.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.accept_redirects = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_redirects_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.accept_redirects\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.default.accept_redirects\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80919-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.default.accept_redirects%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_accept_redirects.conf
overwrite: true
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router,
which can be used to bypass network security measures.
Accepting source-routed packets in the IPv4 protocol has few legitimate
uses. It should be disabled unless it is absolutely required, such as when
IPv4 forwarding is enabled and the system is legitimately functioning as a
router. Identifiers:
CCE-80920-2 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040249, 3.2.1, SV-244552r818863_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80920-2
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040249
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_source_route
- name: Comment out any occurrences of net.ipv4.conf.default.accept_source_route from
/etc/sysctl.d/*.conf files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.accept_source_route
replace: '#net.ipv4.conf.default.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80920-2
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040249
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_source_route
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.accept_source_route is set
sysctl:
name: net.ipv4.conf.default.accept_source_route
value: '{{ sysctl_net_ipv4_conf_default_accept_source_route_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80920-2
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040249
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_source_route
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.default.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.default.accept_source_route" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_default_accept_source_route_value='0'
#
# Set runtime for net.ipv4.conf.default.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_source_route="$sysctl_net_ipv4_conf_default_accept_source_route_value"
#
# If net.ipv4.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.accept_source_route = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_source_route_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.accept_source_route\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.default.accept_source_route\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80920-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.default.accept_source_route%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_accept_source_route.conf
overwrite: true
|
Enable Kernel Paremeter to Log Martian Packets on all IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.log_martians kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.log_martians=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.log_martians = 1 Rationale:The presence of "martian" packets (which have impossible addresses)
as well as spoofed packets, source-routed packets, and redirects could be a
sign of nefarious network activity. Logging these packets enables this activity
to be detected. Identifiers:
CCE-81020-0 References:
1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.04, DSS03.05, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000126, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.11.2.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), SC-5(3)(a), DE.CM-1, PR.AC-3, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, 3.2.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.log_martians.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81020-0
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_conf_default_log_martians
- unknown_severity
- name: Comment out any occurrences of net.ipv4.conf.default.log_martians from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.log_martians
replace: '#net.ipv4.conf.default.log_martians'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81020-0
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_conf_default_log_martians
- unknown_severity
- name: XCCDF Value sysctl_net_ipv4_conf_default_log_martians_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_log_martians_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.log_martians is set
sysctl:
name: net.ipv4.conf.default.log_martians
value: '{{ sysctl_net_ipv4_conf_default_log_martians_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81020-0
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_conf_default_log_martians
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.default.log_martians from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.log_martians.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.default.log_martians" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_default_log_martians_value='1'
#
# Set runtime for net.ipv4.conf.default.log_martians
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.log_martians="$sysctl_net_ipv4_conf_default_log_martians_value"
#
# If net.ipv4.conf.default.log_martians present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.log_martians = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.log_martians")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_log_martians_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.log_martians\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.default.log_martians\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81020-0"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.default.log_martians%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_log_martians.conf
overwrite: true
|
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.rp_filter kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.rp_filter = 1 Rationale:Enabling reverse path filtering drops packets with source addresses
that should not have been able to be received on the interface they were
received on. It should not be used on systems which are routers for
complicated networks, but is helpful for end hosts and routers serving small
networks. Identifiers:
CCE-81022-6 References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, 3.2.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.rp_filter.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81022-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_rp_filter
- name: Comment out any occurrences of net.ipv4.conf.default.rp_filter from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.rp_filter
replace: '#net.ipv4.conf.default.rp_filter'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81022-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_rp_filter
- name: XCCDF Value sysctl_net_ipv4_conf_default_rp_filter_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_rp_filter_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.rp_filter is set
sysctl:
name: net.ipv4.conf.default.rp_filter
value: '{{ sysctl_net_ipv4_conf_default_rp_filter_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81022-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_rp_filter
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.default.rp_filter from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.rp_filter.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.default.rp_filter" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_default_rp_filter_value='1'
#
# Set runtime for net.ipv4.conf.default.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.rp_filter="$sysctl_net_ipv4_conf_default_rp_filter_value"
#
# If net.ipv4.conf.default.rp_filter present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.rp_filter = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.rp_filter")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_rp_filter_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.rp_filter\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.default.rp_filter\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81022-6"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.default.rp_filter%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_rp_filter.conf
overwrite: true
|
Configure Kernel Parameter for Accepting Secure Redirects By Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.secure_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.secure_redirects = 0 Rationale:Accepting "secure" ICMP redirects (from those gateways listed as
default gateways) has few legitimate uses. It should be disabled unless it is
absolutely required. Identifiers:
CCE-81017-6 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, 3.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.secure_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81017-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_secure_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.secure_redirects from
/etc/sysctl.d/*.conf files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.secure_redirects
replace: '#net.ipv4.conf.default.secure_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81017-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_secure_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_default_secure_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_secure_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.secure_redirects is set
sysctl:
name: net.ipv4.conf.default.secure_redirects
value: '{{ sysctl_net_ipv4_conf_default_secure_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81017-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_secure_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.default.secure_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.secure_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.default.secure_redirects" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_conf_default_secure_redirects_value='0'
#
# Set runtime for net.ipv4.conf.default.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.secure_redirects="$sysctl_net_ipv4_conf_default_secure_redirects_value"
#
# If net.ipv4.conf.default.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.secure_redirects = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.secure_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_secure_redirects_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.secure_redirects\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.default.secure_redirects\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81017-6"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.default.secure_redirects%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_secure_redirects.conf
overwrite: true
|
Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.icmp_echo_ignore_broadcasts = 1 Rationale:Responding to broadcast (ICMP) echoes facilitates network mapping
and provides a vector for amplification attacks.
Ignoring ICMP echo requests (pings) sent to broadcast or multicast
addresses makes the system slightly more difficult to enumerate on the network. Identifiers:
CCE-80922-8 References:
1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040230, 3.2.5, SV-230537r818854_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80922-8
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040230
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_icmp_echo_ignore_broadcasts
- name: Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts
replace: '#net.ipv4.icmp_echo_ignore_broadcasts'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80922-8
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040230
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_icmp_echo_ignore_broadcasts
- name: XCCDF Value sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value # promote to variable
set_fact:
sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.icmp_echo_ignore_broadcasts is set
sysctl:
name: net.ipv4.icmp_echo_ignore_broadcasts
value: '{{ sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80922-8
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040230
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_icmp_echo_ignore_broadcasts
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_echo_ignore_broadcasts.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.icmp_echo_ignore_broadcasts" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value='1'
#
# Set runtime for net.ipv4.icmp_echo_ignore_broadcasts
#
/sbin/sysctl -q -n -w net.ipv4.icmp_echo_ignore_broadcasts="$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value"
#
# If net.ipv4.icmp_echo_ignore_broadcasts present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.icmp_echo_ignore_broadcasts = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_echo_ignore_broadcasts")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.icmp_echo_ignore_broadcasts\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.icmp_echo_ignore_broadcasts\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80922-8"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.icmp_echo_ignore_broadcasts%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_icmp_echo_ignore_broadcasts.conf
overwrite: true
|
Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.icmp_ignore_bogus_error_responses = 1 Rationale:Ignoring bogus ICMP error responses reduces
log size, although some activity would not be logged. Identifiers:
CCE-81023-4 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, 3.2.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81023-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
- name: Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses
from /etc/sysctl.d/*.conf files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses
replace: '#net.ipv4.icmp_ignore_bogus_error_responses'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81023-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
- name: XCCDF Value sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value # promote to variable
set_fact:
sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.icmp_ignore_bogus_error_responses is set
sysctl:
name: net.ipv4.icmp_ignore_bogus_error_responses
value: '{{ sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81023-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.icmp_ignore_bogus_error_responses" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value='1'
#
# Set runtime for net.ipv4.icmp_ignore_bogus_error_responses
#
/sbin/sysctl -q -n -w net.ipv4.icmp_ignore_bogus_error_responses="$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"
#
# If net.ipv4.icmp_ignore_bogus_error_responses present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.icmp_ignore_bogus_error_responses = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_ignore_bogus_error_responses")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.icmp_ignore_bogus_error_responses\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.icmp_ignore_bogus_error_responses\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81023-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.icmp_ignore_bogus_error_responses%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_icmp_ignore_bogus_error_responses.conf
overwrite: true
|
Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.tcp_syncookies kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.tcp_syncookies=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.tcp_syncookies = 1 Rationale:A TCP SYN flood attack can cause a denial of service by filling a
system's TCP connection table with connections in the SYN_RCVD state.
Syncookies can be used to track a connection when a subsequent ACK is received,
verifying the initiator is attempting a valid connection and is not a flood
source. This feature is activated when a flood condition is detected, and
enables the system to continue servicing valid connection requests. Identifiers:
CCE-80923-6 References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001095, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), SC-5(1), SC-5(2), SC-5(3)(a), CM-6(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00071, 3.2.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.tcp_syncookies.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80923-6
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
- name: Comment out any occurrences of net.ipv4.tcp_syncookies from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.tcp_syncookies
replace: '#net.ipv4.tcp_syncookies'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80923-6
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
- name: XCCDF Value sysctl_net_ipv4_tcp_syncookies_value # promote to variable
set_fact:
sysctl_net_ipv4_tcp_syncookies_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.tcp_syncookies is set
sysctl:
name: net.ipv4.tcp_syncookies
value: '{{ sysctl_net_ipv4_tcp_syncookies_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80923-6
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.tcp_syncookies from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.tcp_syncookies.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.tcp_syncookies" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_net_ipv4_tcp_syncookies_value='1'
#
# Set runtime for net.ipv4.tcp_syncookies
#
/sbin/sysctl -q -n -w net.ipv4.tcp_syncookies="$sysctl_net_ipv4_tcp_syncookies_value"
#
# If net.ipv4.tcp_syncookies present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.tcp_syncookies = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.tcp_syncookies")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_tcp_syncookies_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.tcp_syncookies\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.tcp_syncookies\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80923-6"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.tcp_syncookies%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_tcp_syncookies.conf
overwrite: true
|
Network Parameters for Hosts Only
[ref]groupIf the system is not going to be used as a router, then setting certain
kernel parameters ensure that the host will not perform routing
of network traffic. |
contains 3 rules |
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.send_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers. Identifiers:
CCE-80918-6 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040220, 3.1.2, SV-230536r818851_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.send_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80918-6
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040220
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.send_redirects from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.send_redirects
replace: '#net.ipv4.conf.all.send_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80918-6
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040220
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
- name: Ensure sysctl net.ipv4.conf.all.send_redirects is set to 0
sysctl:
name: net.ipv4.conf.all.send_redirects
value: '0'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80918-6
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040220
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.send_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.send_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.all.send_redirects" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for net.ipv4.conf.all.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.send_redirects="0"
#
# If net.ipv4.conf.all.send_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.send_redirects = 0" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.send_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.send_redirects\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.all.send_redirects\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80918-6"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.all.send_redirects%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_send_redirects.conf
overwrite: true
|
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.send_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers. Identifiers:
CCE-80921-0 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040270, 3.1.2, SV-230543r818881_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.send_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80921-0
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040270
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.send_redirects from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.send_redirects
replace: '#net.ipv4.conf.default.send_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80921-0
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040270
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
- name: Ensure sysctl net.ipv4.conf.default.send_redirects is set to 0
sysctl:
name: net.ipv4.conf.default.send_redirects
value: '0'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80921-0
- CJIS-5.10.1.1
- DISA-STIG-RHEL-08-040270
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.default.send_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.send_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.conf.default.send_redirects" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for net.ipv4.conf.default.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.send_redirects="0"
#
# If net.ipv4.conf.default.send_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.default.send_redirects = 0" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.send_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.send_redirects\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.conf.default.send_redirects\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80921-0"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.ipv4.conf.default.send_redirects%3D0%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_send_redirects.conf
overwrite: true
|
Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.ip_forward=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.ip_forward = 0 Warning:
Certain technologies such as virtual machines, containers, etc. rely on IPv4 forwarding to enable and use networking.
Disabling IPv4 forwarding would cause those technologies to stop working. Therefore, this rule should not be used in
profiles or benchmarks that target usage of IPv4 forwarding. Warning:
This rule is disabled on Red Hat Virtualization Hosts and Managers, it will report not applicable.
RHV host requires IPv4 forwarding for the Hosted Engine bootstrap VM to reach network outside of the initial host. Rationale:Routing protocol daemons are typically used on routers to exchange
network topology information with other routers. If this capability is used when
not required, system network information may be unnecessarily transmitted across
the network. Identifiers:
CCE-81024-2 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, RHEL-08-040260, 3.1.1, SV-230540r818872_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*net.ipv4.ip_forward.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81024-2
- DISA-STIG-RHEL-08-040260
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
- name: Comment out any occurrences of net.ipv4.ip_forward from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.ip_forward
replace: '#net.ipv4.ip_forward'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81024-2
- DISA-STIG-RHEL-08-040260
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
- name: Ensure sysctl net.ipv4.ip_forward is set to 0
sysctl:
name: net.ipv4.ip_forward
value: '0'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81024-2
- DISA-STIG-RHEL-08-040260
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.ip_forward from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.ip_forward.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.ipv4.ip_forward" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for net.ipv4.ip_forward
#
/sbin/sysctl -q -n -w net.ipv4.ip_forward="0"
#
# If net.ipv4.ip_forward present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.ip_forward = 0" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.ip_forward")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.ip_forward\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.ipv4.ip_forward\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-81024-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Uncommon Network Protocols
[ref]groupThe system includes support for several network protocols which are not commonly used.
Although security vulnerabilities in kernel networking code are not frequently discovered,
the consequences can be dramatic. Ensuring uncommon network protocols are disabled
reduces the system's risk to attacks targeted at its implementation of those protocols. Warning:
Although these protocols are not commonly used, avoid disruption
in your network environment by ensuring they are not needed
prior to disabling them. |
contains 4 rules |
Disable DCCP Support
[ref]ruleThe Datagram Congestion Control Protocol (DCCP) is a
relatively new transport layer protocol, designed to support
streaming media and telephony.
To configure the system to prevent the dccp
kernel module from being loaded, add the following line to the file /etc/modprobe.d/dccp.conf :
install dccp /bin/true Rationale:Disabling DCCP protects
the system against exploitation of any flaws in its implementation. Identifiers:
CCE-80833-7 References:
11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, CCI-001958, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000096-GPOS-00050, SRG-OS-000378-GPOS-00163, 3.3.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'dccp' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/dccp.conf
regexp: dccp
line: install dccp /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80833-7
- CJIS-5.10.1
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- kernel_module_dccp_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install dccp" /etc/modprobe.d/dccp.conf ; then
sed -i 's#^install dccp.*#install dccp /bin/true#g' /etc/modprobe.d/dccp.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/dccp.conf
echo "install dccp /bin/true" >> /etc/modprobe.d/dccp.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,install%20dccp%20/bin/true%0A
mode: 0644
path: /etc/modprobe.d/75-kernel_module_dccp_disabled.conf
overwrite: true
|
Disable RDS Support
[ref]ruleThe Reliable Datagram Sockets (RDS) protocol is a transport
layer protocol designed to provide reliable high-bandwidth,
low-latency communications between nodes in a cluster.
To configure the system to prevent the rds
kernel module from being loaded, add the following line to the file /etc/modprobe.d/rds.conf :
install rds /bin/true Rationale:Disabling RDS protects
the system against exploitation of any flaws in its implementation. Identifiers:
CCE-82870-7 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 3.3.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'rds' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/rds.conf
regexp: rds
line: install rds /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82870-7
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- kernel_module_rds_disabled
- low_complexity
- low_severity
- medium_disruption
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install rds" /etc/modprobe.d/rds.conf ; then
sed -i 's#^install rds.*#install rds /bin/true#g' /etc/modprobe.d/rds.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/rds.conf
echo "install rds /bin/true" >> /etc/modprobe.d/rds.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,install%20rds%20/bin/true%0A
mode: 0644
path: /etc/modprobe.d/75-kernel_module_rds_disabled.conf
overwrite: true
|
Disable SCTP Support
[ref]ruleThe Stream Control Transmission Protocol (SCTP) is a
transport layer protocol, designed to support the idea of
message-oriented communication, with several streams of messages
within one connection.
To configure the system to prevent the sctp
kernel module from being loaded, add the following line to the file /etc/modprobe.d/sctp.conf :
install sctp /bin/true Rationale:Disabling SCTP protects
the system against exploitation of any flaws in its implementation. Identifiers:
CCE-80834-5 References:
11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, CCI-000381, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000095-GPOS-00049, RHEL-08-040023, 3.3.2, SV-230496r792917_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'sctp' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/sctp.conf
regexp: sctp
line: install sctp /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80834-5
- CJIS-5.10.1
- DISA-STIG-RHEL-08-040023
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- kernel_module_sctp_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install sctp" /etc/modprobe.d/sctp.conf ; then
sed -i 's#^install sctp.*#install sctp /bin/true#g' /etc/modprobe.d/sctp.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/sctp.conf
echo "install sctp /bin/true" >> /etc/modprobe.d/sctp.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,install%20sctp%20/bin/true%0A
mode: 0644
path: /etc/modprobe.d/75-kernel_module_sctp_disabled.conf
overwrite: true
|
Disable TIPC Support
[ref]ruleThe Transparent Inter-Process Communication (TIPC) protocol
is designed to provide communications between nodes in a
cluster.
To configure the system to prevent the tipc
kernel module from being loaded, add the following line to the file /etc/modprobe.d/tipc.conf :
install tipc /bin/true Warning:
This configuration baseline was created to deploy the base operating system for general purpose
workloads. When the operating system is configured for certain purposes, such as
a node in High Performance Computing cluster, it is expected that
the tipc kernel module will be loaded. Rationale:Disabling TIPC protects
the system against exploitation of any flaws in its implementation. Identifiers:
CCE-82297-3 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000381, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, FMT_SMF_EXT.1, SRG-OS-000095-GPOS-00049, RHEL-08-040024, 3.3.4, SV-230497r792920_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'tipc' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/tipc.conf
regexp: tipc
line: install tipc /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82297-3
- DISA-STIG-RHEL-08-040024
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- kernel_module_tipc_disabled
- low_complexity
- low_severity
- medium_disruption
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install tipc" /etc/modprobe.d/tipc.conf ; then
sed -i 's#^install tipc.*#install tipc /bin/true#g' /etc/modprobe.d/tipc.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/tipc.conf
echo "install tipc /bin/true" >> /etc/modprobe.d/tipc.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,install%20tipc%20/bin/true%0A
mode: 0644
path: /etc/modprobe.d/75-kernel_module_tipc_disabled.conf
overwrite: true
|
Wireless Networking
[ref]groupWireless networking, such as 802.11
(WiFi) and Bluetooth, can present a security risk to sensitive or
classified systems and networks. Wireless networking hardware is
much more likely to be included in laptop or portable systems than
in desktops or servers.
Removal of hardware provides the greatest assurance that the wireless
capability remains disabled. Acquisition policies often include provisions to
prevent the purchase of equipment that will be used in sensitive spaces and
includes wireless capabilities. If it is impractical to remove the wireless
hardware, and policy permits the device to enter sensitive spaces as long
as wireless is disabled, efforts should instead focus on disabling wireless capability
via software. |
contains 1 rule |
Disable Wireless Through Software Configuration
[ref]groupIf it is impossible to remove the wireless hardware
from the device in question, disable as much of it as possible
through software. The following methods can disable software
support for wireless networking, but note that these methods do not
prevent malicious software or careless users from re-activating the
devices. |
contains 1 rule |
Deactivate Wireless Network Interfaces
[ref]ruleDeactivating wireless network interfaces should prevent normal usage of the wireless
capability.
Configure the system to disable all wireless network interfaces with the following command:
$ sudo nmcli radio all off Rationale:The use of wireless networking can introduce many different attack vectors into
the organization's network. Common attack vectors such as malicious association
and ad hoc networks will allow an attacker to spoof a wireless access point
(AP), allowing validated systems to connect to the malicious AP and enabling the
attacker to monitor and record network traffic. These malicious APs can also
serve to create a man-in-the-middle attack or be used to create a denial of
service to valid network resources. Identifiers:
CCE-83501-7 References:
11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.16, CCI-000085, CCI-002418, CCI-002421, CCI-001444, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 1315, 1319, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000424-GPOS-00188, SRG-OS-000481-GPOS-000481, RHEL-08-040110, 3.5, SV-230506r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Deactivate Wireless Network Interfaces
command: nmcli radio wifi off
tags:
- CCE-83501-7
- DISA-STIG-RHEL-08-040110
- NIST-800-171-3.1.16
- NIST-800-53-AC-18(3)
- NIST-800-53-AC-18(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- wireless_disable_interfaces
Remediation Shell script: (show)
|
File Permissions and Masks
[ref]groupTraditional Unix security relies heavily on file and
directory permissions to prevent unauthorized users from reading or
modifying files to which they should not have access.
Several of the commands in this section search filesystems
for files or directories with certain characteristics, and are
intended to be run on every local partition on a given system.
When the variable PART appears in one of the commands below,
it means that the command is intended to be run repeatedly, with the
name of each local partition substituted for PART in turn.
The following command prints a list of all xfs partitions on the local
system, which is the default filesystem for Red Hat Enterprise Linux 8
installations:
$ mount -t xfs | awk '{print $3}'
For any systems that use a different
local filesystem type, modify this command as appropriate. |
contains 48 rules |
Verify Permissions on Important Files and
Directories
[ref]groupPermissions for many files on a system must be set
restrictively to ensure sensitive information is properly protected.
This section discusses important
permission restrictions which can be verified
to ensure that no harmful discrepancies have
arisen. |
contains 28 rules |
Verify Permissions on Files with Local Account Information and Credentials
[ref]groupThe default restrictive permissions for files which act as
important security databases such as passwd , shadow ,
group , and gshadow files must be maintained. Many utilities
need read access to the passwd file in order to function properly, but
read access to the shadow file allows malicious attacks against system
passwords, and should never be enabled. |
contains 24 rules |
Verify Group Who Owns Backup group File
[ref]rule To properly set the group owner of /etc/group- , run the command: $ sudo chgrp root /etc/group- Rationale:The /etc/group- file is a backup file of /etc/group , and as such,
it contains information regarding groups that are configured on the system.
Protection of this file is important for system security. Identifiers:
CCE-83475-4 References:
6.1.9 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group-
stat:
path: /etc/group-
register: file_exists
tags:
- CCE-83475-4
- configure_strategy
- file_groupowner_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/group-
file:
path: /etc/group-
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83475-4
- configure_strategy
- file_groupowner_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/group-
|
Verify Group Who Owns Backup gshadow File
[ref]rule To properly set the group owner of /etc/gshadow- , run the command: $ sudo chgrp root /etc/gshadow- Rationale:The /etc/gshadow- file is a backup of /etc/gshadow , and as such,
it contains group password hashes. Protection of this file is critical for system security. Identifiers:
CCE-83535-5 References:
6.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/gshadow-
stat:
path: /etc/gshadow-
register: file_exists
tags:
- CCE-83535-5
- configure_strategy
- file_groupowner_backup_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/gshadow-
file:
path: /etc/gshadow-
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83535-5
- configure_strategy
- file_groupowner_backup_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/gshadow-
|
Verify Group Who Owns Backup passwd File
[ref]rule To properly set the group owner of /etc/passwd- , run the command: $ sudo chgrp root /etc/passwd- Rationale:The /etc/passwd- file is a backup file of /etc/passwd , and as such,
it contains information about the users that are configured on the system.
Protection of this file is critical for system security. Identifiers:
CCE-83324-4 References:
6.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd-
stat:
path: /etc/passwd-
register: file_exists
tags:
- CCE-83324-4
- configure_strategy
- file_groupowner_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/passwd-
file:
path: /etc/passwd-
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83324-4
- configure_strategy
- file_groupowner_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/passwd-
|
Verify User Who Owns Backup shadow File
[ref]rule To properly set the group owner of /etc/shadow- , run the command: $ sudo chgrp root /etc/shadow- Rationale:The /etc/shadow- file is a backup file of /etc/shadow , and as such,
it contains the list of local system accounts and password hashes.
Protection of this file is critical for system security. Identifiers:
CCE-83415-0 References:
6.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow-
stat:
path: /etc/shadow-
register: file_exists
tags:
- CCE-83415-0
- configure_strategy
- file_groupowner_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/shadow-
file:
path: /etc/shadow-
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83415-0
- configure_strategy
- file_groupowner_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/shadow-
|
Verify Group Who Owns group File
[ref]rule To properly set the group owner of /etc/group , run the command: $ sudo chgrp root /etc/group Rationale:The /etc/group file contains information regarding groups that are configured
on the system. Protection of this file is important for system security. Identifiers:
CCE-80796-6 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group
stat:
path: /etc/group
register: file_exists
tags:
- CCE-80796-6
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_groupowner_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/group
file:
path: /etc/group
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80796-6
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_groupowner_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/group
|
Verify Group Who Owns gshadow File
[ref]rule To properly set the group owner of /etc/gshadow , run the command: $ sudo chgrp root /etc/gshadow Rationale:The /etc/gshadow file contains group password hashes. Protection of this file
is critical for system security. Identifiers:
CCE-80797-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 6.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/gshadow
stat:
path: /etc/gshadow
register: file_exists
tags:
- CCE-80797-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/gshadow
file:
path: /etc/gshadow
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80797-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/gshadow
|
Verify Group Who Owns passwd File
[ref]rule To properly set the group owner of /etc/passwd , run the command: $ sudo chgrp root /etc/passwd Rationale:The /etc/passwd file contains information about the users that are configured on
the system. Protection of this file is critical for system security. Identifiers:
CCE-80798-2 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd
stat:
path: /etc/passwd
register: file_exists
tags:
- CCE-80798-2
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_groupowner_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/passwd
file:
path: /etc/passwd
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80798-2
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_groupowner_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/passwd
|
Verify Group Who Owns shadow File
[ref]rule To properly set the group owner of /etc/shadow , run the command: $ sudo chgrp root /etc/shadow Rationale:The /etc/shadow file stores password hashes. Protection of this file is
critical for system security. Identifiers:
CCE-80799-0 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow
stat:
path: /etc/shadow
register: file_exists
tags:
- CCE-80799-0
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_groupowner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/shadow
file:
path: /etc/shadow
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80799-0
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_groupowner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/shadow
|
Verify User Who Owns Backup group File
[ref]rule To properly set the owner of /etc/group- , run the command: $ sudo chown root /etc/group- Rationale:The /etc/group- file is a backup file of /etc/group , and as such,
it contains information regarding groups that are configured on the system.
Protection of this file is important for system security. Identifiers:
CCE-83473-9 References:
6.1.9 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group-
stat:
path: /etc/group-
register: file_exists
tags:
- CCE-83473-9
- configure_strategy
- file_owner_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/group-
file:
path: /etc/group-
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83473-9
- configure_strategy
- file_owner_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/group-
|
Verify User Who Owns Backup gshadow File
[ref]rule To properly set the owner of /etc/gshadow- , run the command: $ sudo chown root /etc/gshadow- Rationale:The /etc/gshadow- file is a backup of /etc/gshadow , and as such,
it contains group password hashes. Protection of this file is critical for system security. Identifiers:
CCE-83533-0 References:
6.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/gshadow-
stat:
path: /etc/gshadow-
register: file_exists
tags:
- CCE-83533-0
- configure_strategy
- file_owner_backup_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/gshadow-
file:
path: /etc/gshadow-
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83533-0
- configure_strategy
- file_owner_backup_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/gshadow-
|
Verify User Who Owns Backup passwd File
[ref]rule To properly set the owner of /etc/passwd- , run the command: $ sudo chown root /etc/passwd- Rationale:The /etc/passwd- file is a backup file of /etc/passwd , and as such,
it contains information about the users that are configured on the system.
Protection of this file is critical for system security. Identifiers:
CCE-83326-9 References:
6.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd-
stat:
path: /etc/passwd-
register: file_exists
tags:
- CCE-83326-9
- configure_strategy
- file_owner_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/passwd-
file:
path: /etc/passwd-
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83326-9
- configure_strategy
- file_owner_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/passwd-
|
Verify Group Who Owns Backup shadow File
[ref]rule To properly set the owner of /etc/shadow- , run the command: $ sudo chown root /etc/shadow- Rationale:The /etc/shadow- file is a backup file of /etc/shadow , and as such,
it contains the list of local system accounts and password hashes.
Protection of this file is critical for system security. Identifiers:
CCE-83413-5 References:
6.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow-
stat:
path: /etc/shadow-
register: file_exists
tags:
- CCE-83413-5
- configure_strategy
- file_owner_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/shadow-
file:
path: /etc/shadow-
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83413-5
- configure_strategy
- file_owner_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/shadow-
|
Verify User Who Owns group File
[ref]rule To properly set the owner of /etc/group , run the command: $ sudo chown root /etc/group Rationale:The /etc/group file contains information regarding groups that are configured
on the system. Protection of this file is important for system security. Identifiers:
CCE-80801-4 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group
stat:
path: /etc/group
register: file_exists
tags:
- CCE-80801-4
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_owner_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/group
file:
path: /etc/group
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80801-4
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_owner_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/group
|
Verify User Who Owns gshadow File
[ref]rule To properly set the owner of /etc/gshadow , run the command: $ sudo chown root /etc/gshadow Rationale:The /etc/gshadow file contains group password hashes. Protection of this file
is critical for system security. Identifiers:
CCE-80802-2 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 6.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/gshadow
stat:
path: /etc/gshadow
register: file_exists
tags:
- CCE-80802-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/gshadow
file:
path: /etc/gshadow
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80802-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/gshadow
|
Verify User Who Owns passwd File
[ref]rule To properly set the owner of /etc/passwd , run the command: $ sudo chown root /etc/passwd Rationale:The /etc/passwd file contains information about the users that are configured on
the system. Protection of this file is critical for system security. Identifiers:
CCE-80803-0 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd
stat:
path: /etc/passwd
register: file_exists
tags:
- CCE-80803-0
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_owner_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/passwd
file:
path: /etc/passwd
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80803-0
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_owner_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/passwd
|
Verify User Who Owns shadow File
[ref]rule To properly set the owner of /etc/shadow , run the command: $ sudo chown root /etc/shadow Rationale:The /etc/shadow file contains the list of local
system accounts and stores password hashes. Protection of this file is
critical for system security. Failure to give ownership of this file
to root provides the designated owner with access to sensitive information
which could weaken the system security posture. Identifiers:
CCE-80804-8 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow
stat:
path: /etc/shadow
register: file_exists
tags:
- CCE-80804-8
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/shadow
file:
path: /etc/shadow
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80804-8
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/shadow
|
Verify Permissions on Backup group File
[ref]rule
To properly set the permissions of /etc/group- , run the command:
$ sudo chmod 0644 /etc/group- Rationale:The /etc/group- file is a backup file of /etc/group , and as such,
it contains information regarding groups that are configured on the system.
Protection of this file is important for system security. Identifiers:
CCE-83483-8 References:
6.1.9 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group-
stat:
path: /etc/group-
register: file_exists
tags:
- CCE-83483-8
- configure_strategy
- file_permissions_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/group-
file:
path: /etc/group-
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83483-8
- configure_strategy
- file_permissions_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/group-
|
Verify Permissions on Backup gshadow File
[ref]rule
To properly set the permissions of /etc/gshadow- , run the command:
$ sudo chmod 0000 /etc/gshadow- Rationale:The /etc/gshadow- file is a backup of /etc/gshadow , and as such,
it contains group password hashes. Protection of this file is critical for system security. Identifiers:
CCE-83573-6 References:
6.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/gshadow-
stat:
path: /etc/gshadow-
register: file_exists
tags:
- CCE-83573-6
- configure_strategy
- file_permissions_backup_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xwrs,g-xwrs,o-xwrt on /etc/gshadow-
file:
path: /etc/gshadow-
mode: u-xwrs,g-xwrs,o-xwrt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83573-6
- configure_strategy
- file_permissions_backup_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xwrs,g-xwrs,o-xwrt /etc/gshadow-
|
Verify Permissions on Backup passwd File
[ref]rule
To properly set the permissions of /etc/passwd- , run the command:
$ sudo chmod 0644 /etc/passwd- Rationale:The /etc/passwd- file is a backup file of /etc/passwd , and as such,
it contains information about the users that are configured on the system.
Protection of this file is critical for system security. Identifiers:
CCE-83332-7 References:
6.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd-
stat:
path: /etc/passwd-
register: file_exists
tags:
- CCE-83332-7
- configure_strategy
- file_permissions_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/passwd-
file:
path: /etc/passwd-
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83332-7
- configure_strategy
- file_permissions_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/passwd-
|
Verify Permissions on Backup shadow File
[ref]rule
To properly set the permissions of /etc/shadow- , run the command:
$ sudo chmod 0000 /etc/shadow- Rationale:The /etc/shadow- file is a backup file of /etc/shadow , and as such,
it contains the list of local system accounts and password hashes.
Protection of this file is critical for system security. Identifiers:
CCE-83417-6 References:
6.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow-
stat:
path: /etc/shadow-
register: file_exists
tags:
- CCE-83417-6
- configure_strategy
- file_permissions_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xwrs,g-xwrs,o-xwrt on /etc/shadow-
file:
path: /etc/shadow-
mode: u-xwrs,g-xwrs,o-xwrt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-83417-6
- configure_strategy
- file_permissions_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xwrs,g-xwrs,o-xwrt /etc/shadow-
|
Verify Permissions on group File
[ref]rule
To properly set the permissions of /etc/passwd , run the command:
$ sudo chmod 0644 /etc/passwd Rationale:The /etc/group file contains information regarding groups that are configured
on the system. Protection of this file is important for system security. Identifiers:
CCE-80810-5 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group
stat:
path: /etc/group
register: file_exists
tags:
- CCE-80810-5
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_permissions_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/group
file:
path: /etc/group
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80810-5
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_permissions_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/group
|
Verify Permissions on gshadow File
[ref]rule
To properly set the permissions of /etc/gshadow , run the command:
$ sudo chmod 0000 /etc/gshadow Rationale:The /etc/gshadow file contains group password hashes. Protection of this file
is critical for system security. Identifiers:
CCE-80811-3 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 6.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/gshadow
stat:
path: /etc/gshadow
register: file_exists
tags:
- CCE-80811-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xwrs,g-xwrs,o-xwrt on /etc/gshadow
file:
path: /etc/gshadow
mode: u-xwrs,g-xwrs,o-xwrt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80811-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xwrs,g-xwrs,o-xwrt /etc/gshadow
|
Verify Permissions on passwd File
[ref]rule
To properly set the permissions of /etc/passwd , run the command:
$ sudo chmod 0644 /etc/passwd Rationale:If the /etc/passwd file is writable by a group-owner or the
world the risk of its compromise is increased. The file contains the list of
accounts on the system and associated information, and protection of this file
is critical for system security. Identifiers:
CCE-80812-1 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd
stat:
path: /etc/passwd
register: file_exists
tags:
- CCE-80812-1
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_permissions_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/passwd
file:
path: /etc/passwd
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80812-1
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_permissions_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/passwd
|
Verify Permissions on shadow File
[ref]rule
To properly set the permissions of /etc/shadow , run the command:
$ sudo chmod 0000 /etc/shadow Rationale:The /etc/shadow file contains the list of local
system accounts and stores password hashes. Protection of this file is
critical for system security. Failure to give ownership of this file
to root provides the designated owner with access to sensitive information
which could weaken the system security posture. Identifiers:
CCE-80813-9 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 6.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow
stat:
path: /etc/shadow
register: file_exists
tags:
- CCE-80813-9
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_permissions_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xwrs,g-xwrs,o-xwrt on /etc/shadow
file:
path: /etc/shadow
mode: u-xwrs,g-xwrs,o-xwrt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-80813-9
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- configure_strategy
- file_permissions_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xwrs,g-xwrs,o-xwrt /etc/shadow
|
Verify that All World-Writable Directories Have Sticky Bits Set
[ref]ruleWhen the so-called 'sticky bit' is set on a directory,
only the owner of a given file may remove that file from the
directory. Without the sticky bit, any user with write access to a
directory may remove any file in the directory. Setting the sticky
bit prevents users from removing each other's files. In cases where
there is no reason for a directory to be world-writable, a better
solution is to remove that permission rather than to set the sticky
bit. However, if a directory is used by a particular application,
consult that application's documentation instead of blindly
changing modes.
To set the sticky bit on a world-writable directory DIR, run the
following command:
$ sudo chmod +t DIR Rationale:Failing to set the sticky bit on public directories allows unauthorized
users to delete files in the directory structure.
The only authorized public directories are those temporary directories
supplied with the system, or those designed to be temporary file
repositories. The setting is normally reserved for directories used by the
system, by users for temporary file storage (such as /tmp ), and
for directories requiring global read/write access. Identifiers:
CCE-80783-4 References:
BP28(R40), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001090, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000138-GPOS-00069, RHEL-08-010190, 1.1.21, SV-230243r792857_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Get all world-writable directories with no sticky bits set
shell: |
set -o pipefail
df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -type d \( -perm -0002 -a ! -perm -1000 \) 2>/dev/null
register: dir_output
tags:
- CCE-80783-4
- DISA-STIG-RHEL-08-010190
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: ensure sticky bit is set
file:
path: '{{ item }}'
mode: a+t
with_items:
- '{{ dir_output.stdout_lines }}'
tags:
- CCE-80783-4
- DISA-STIG-RHEL-08-010190
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
df --local -P | awk '{if (NR!=1) print $6}' \
| xargs -I '{}' find '{}' -xdev -type d \
\( -perm -0002 -a ! -perm -1000 \) 2>/dev/null \
| xargs chmod a+t
|
Ensure No World-Writable Files Exist
[ref]ruleIt is generally a good idea to remove global (other) write
access to a file when it is discovered. However, check with
documentation for specific applications before making changes.
Also, monitor for recurring world-writable files, as these may be
symptoms of a misconfigured application or user account. Finally,
this applies to real files and not virtual files that are a part of
pseudo file systems such as sysfs or procfs . Rationale:Data in world-writable files can be modified by any
user on the system. In almost all circumstances, files can be
configured using a combination of user and group permissions to
support whatever legitimate access is needed without the risk
caused by world-writable files. Identifiers:
CCE-80818-8 References:
BP28(R40), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 6.1.10 Remediation Shell script: (show)
find / -xdev -type f -perm -002 -exec chmod o-w {} \;
|
Ensure All Files Are Owned by a Group
[ref]ruleIf any files are not owned by a group, then the
cause of their lack of group-ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group. The following command will discover and print
any files on local partitions which do not belong to a valid group:
$ df --local -P | awk '{if (NR!=1) print $6}' | sudo xargs -I '{}' find '{}' -xdev -nogroup
To search all filesystems on a system including network mounted
filesystems the following command can be run manually for each partition:
$ sudo find PARTITION -xdev -nogroup Warning:
This rule only considers local groups.
If you have your groups defined outside /etc/group , the rule won't consider those. Rationale:Unowned files do not directly imply a security problem, but they are generally
a sign that something is amiss. They may
be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging
to a deleted account. The files should be repaired so they
will not cause problems when accounts are created in the future,
and the cause should be discovered and addressed. Identifiers:
CCE-83497-8 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, CCI-000366, CCI-002165, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, SRG-OS-000480-GPOS-00227, RHEL-08-010790, 6.1.12, SV-230327r627750_rule |
Ensure All Files Are Owned by a User
[ref]ruleIf any files are not owned by a user, then the
cause of their lack of ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate user. The following command will discover and print
any files on local partitions which do not belong to a valid user:
$ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nouser
To search all filesystems on a system including network mounted
filesystems the following command can be run manually for each partition:
$ sudo find PARTITION -xdev -nouser Warning:
For this rule to evaluate centralized user accounts, getent must be working properly
so that running the command getent passwd returns a list of all users in your organization.
If using the System Security Services Daemon (SSSD), enumerate = true must be configured
in your organization's domain to return a complete list of users Warning:
Enabling this rule will result in slower scan times depending on the size of your organization
and number of centralized users. Rationale:Unowned files do not directly imply a security problem, but they are generally
a sign that something is amiss. They may
be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging
to a deleted account. The files should be repaired so they
will not cause problems when accounts are created in the future,
and the cause should be discovered and addressed. Identifiers:
CCE-83499-4 References:
11, 12, 13, 14, 15, 16, 18, 3, 5, 9, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, CCI-000366, CCI-002165, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, RHEL-08-010780, 6.1.11, SV-230326r627750_rule |
Restrict Dynamic Mounting and Unmounting of
Filesystems
[ref]groupLinux includes a number of facilities for the automated addition
and removal of filesystems on a running system. These facilities may be
necessary in many environments, but this capability also carries some risk -- whether direct
risk from allowing users to introduce arbitrary filesystems,
or risk that software flaws in the automated mount facility itself could
allow an attacker to compromise the system.
This command can be used to list the types of filesystems that are
available to the currently executing kernel:
$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'
If these filesystems are not required then they can be explicitly disabled
in a configuratio file in /etc/modprobe.d . |
contains 5 rules |
Disable the Automounter
[ref]ruleThe autofs daemon mounts and unmounts filesystems, such as user
home directories shared via NFS, on demand. In addition, autofs can be used to handle
removable media, and the default configuration provides the cdrom device as /misc/cd .
However, this method of providing access to removable media is not common, so autofs
can almost always be disabled if NFS is not in use. Even if NFS is required, it may be
possible to configure filesystem mounts statically by editing /etc/fstab
rather than relying on the automounter.
The autofs service can be disabled with the following command:
$ sudo systemctl mask --now autofs.service Rationale:Disabling the automounter permits the administrator to
statically control filesystem mounting through /etc/fstab .
Additionally, automatically mounting filesystems permits easy introduction of
unknown devices, thereby facilitating malicious activity. Identifiers:
CCE-80873-3 References:
1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.4.6, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, RHEL-08-040070, 1.1.22, SV-230502r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service autofs
block:
- name: Disable service autofs
systemd:
name: autofs.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80873-3
- DISA-STIG-RHEL-08-040070
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_autofs_disabled
- name: Unit Socket Exists - autofs.socket
command: systemctl list-unit-files autofs.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80873-3
- DISA-STIG-RHEL-08-040070
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_autofs_disabled
- name: Disable socket autofs
systemd:
name: autofs.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"autofs.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-80873-3
- DISA-STIG-RHEL-08-040070
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_autofs_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'autofs.service'
"$SYSTEMCTL_EXEC" disable 'autofs.service'
"$SYSTEMCTL_EXEC" mask 'autofs.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^autofs.socket'; then
"$SYSTEMCTL_EXEC" stop 'autofs.socket'
"$SYSTEMCTL_EXEC" mask 'autofs.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'autofs.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- enabled: false
name: autofs.service
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_autofs
class disable_autofs {
service {'autofs':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["autofs"]
|
Disable Mounting of cramfs
[ref]rule
To configure the system to prevent the cramfs
kernel module from being loaded, add the following line to the file /etc/modprobe.d/cramfs.conf :
install cramfs /bin/true
This effectively prevents usage of this uncommon filesystem.
The cramfs filesystem type is a compressed read-only
Linux filesystem embedded in small footprint systems. A
cramfs image can be used without having to first
decompress the image.Rationale:Removing support for unneeded filesystem types reduces the local attack surface
of the server. Identifiers:
CCE-81031-7 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, CCI-000381, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000095-GPOS-00049, RHEL-08-040025, 1.1.1.1, SV-230498r792922_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'cramfs' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/cramfs.conf
regexp: cramfs
line: install cramfs /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81031-7
- DISA-STIG-RHEL-08-040025
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- kernel_module_cramfs_disabled
- low_complexity
- low_severity
- medium_disruption
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install cramfs" /etc/modprobe.d/cramfs.conf ; then
sed -i 's#^install cramfs.*#install cramfs /bin/true#g' /etc/modprobe.d/cramfs.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/cramfs.conf
echo "install cramfs /bin/true" >> /etc/modprobe.d/cramfs.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,install%20cramfs%20/bin/true%0A
mode: 0644
path: /etc/modprobe.d/75-kernel_module_cramfs_disabled.conf
overwrite: true
|
Disable Mounting of squashfs
[ref]rule
To configure the system to prevent the squashfs
kernel module from being loaded, add the following line to the file /etc/modprobe.d/squashfs.conf :
install squashfs /bin/true
This effectively prevents usage of this uncommon filesystem.
The squashfs filesystem type is a compressed read-only Linux
filesystem embedded in small footprint systems (similar to
cramfs ). A squashfs image can be used without having
to first decompress the image.Rationale:Removing support for unneeded filesystem types reduces the local attack
surface of the system. Identifiers:
CCE-83498-6 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 1.1.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'squashfs' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/squashfs.conf
regexp: squashfs
line: install squashfs /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83498-6
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- kernel_module_squashfs_disabled
- low_complexity
- low_severity
- medium_disruption
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install squashfs" /etc/modprobe.d/squashfs.conf ; then
sed -i 's#^install squashfs.*#install squashfs /bin/true#g' /etc/modprobe.d/squashfs.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/squashfs.conf
echo "install squashfs /bin/true" >> /etc/modprobe.d/squashfs.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,install%20squashfs%20/bin/true%0A
mode: 0644
path: /etc/modprobe.d/75-kernel_module_squashfs_disabled.conf
overwrite: true
|
Disable Mounting of udf
[ref]rule
To configure the system to prevent the udf
kernel module from being loaded, add the following line to the file /etc/modprobe.d/udf.conf :
install udf /bin/true
This effectively prevents usage of this uncommon filesystem.
The udf filesystem type is the universal disk format
used to implement the ISO/IEC 13346 and ECMA-167 specifications.
This is an open vendor filesystem type for data storage on a broad
range of media. This filesystem type is neccessary to support
writing DVDs and newer optical disc formats.Rationale:Removing support for unneeded filesystem types reduces the local
attack surface of the system. Identifiers:
CCE-82729-5 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 1.1.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'udf' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/udf.conf
regexp: udf
line: install udf /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82729-5
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- kernel_module_udf_disabled
- low_complexity
- low_severity
- medium_disruption
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install udf" /etc/modprobe.d/udf.conf ; then
sed -i 's#^install udf.*#install udf /bin/true#g' /etc/modprobe.d/udf.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/udf.conf
echo "install udf /bin/true" >> /etc/modprobe.d/udf.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,install%20udf%20/bin/true%0A
mode: 0644
path: /etc/modprobe.d/75-kernel_module_udf_disabled.conf
overwrite: true
|
Disable Modprobe Loading of USB Storage Driver
[ref]ruleTo prevent USB storage devices from being used, configure the kernel module loading system
to prevent automatic loading of the USB storage driver.
To configure the system to prevent the usb-storage
kernel module from being loaded, add the following line to the file /etc/modprobe.d/usb-storage.conf :
install usb-storage /bin/true
This will prevent the modprobe program from loading the usb-storage
module, but will not prevent an administrator (or another program) from using the
insmod program to load the module manually.Rationale:USB storage devices such as thumb drives can be used to introduce
malicious software. Identifiers:
CCE-80835-2 References:
1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.21, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, RHEL-08-040080, 1.1.23, SV-230503r809319_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'usb-storage' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/usb-storage.conf
regexp: usb-storage
line: install usb-storage /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80835-2
- DISA-STIG-RHEL-08-040080
- NIST-800-171-3.1.21
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- disable_strategy
- kernel_module_usb-storage_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install usb-storage" /etc/modprobe.d/usb-storage.conf ; then
sed -i 's#^install usb-storage.*#install usb-storage /bin/true#g' /etc/modprobe.d/usb-storage.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/usb-storage.conf
echo "install usb-storage /bin/true" >> /etc/modprobe.d/usb-storage.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,install%20usb-storage%20/bin/true%0A
mode: 0644
path: /etc/modprobe.d/75-kernel_module_usb-storage_disabled.conf
overwrite: true
|
Restrict Partition Mount Options
[ref]groupSystem partitions can be mounted with certain options
that limit what files on those partitions can do. These options
are set in the /etc/fstab configuration file, and can be
used to make certain types of malicious behavior more difficult. |
contains 10 rules |
Add nodev Option to /dev/shm
[ref]ruleThe nodev mount option can be used to prevent creation of device
files in /dev/shm . Legitimate character and block devices should
not exist within temporary directories like /dev/shm .
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm . Rationale:The only legitimate location for device files is the /dev directory
located on the root partition. The only exception to this is chroot jails. Identifiers:
CCE-80837-8 References:
11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, RHEL-08-040120, 1.1.15, SV-230508r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nodev Option to /dev/shm: Check information associated to mountpoint'
command: findmnt '/dev/shm'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80837-8
- DISA-STIG-RHEL-08-040120
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
- name: 'Add nodev Option to /dev/shm: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-80837-8
- DISA-STIG-RHEL-08-040120
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
- name: 'Add nodev Option to /dev/shm: If /dev/shm not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /dev/shm
- tmpfs
- tmpfs
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-80837-8
- DISA-STIG-RHEL-08-040120
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
- name: 'Add nodev Option to /dev/shm: Make sure nodev option is part of the to /dev/shm
options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nodev" not in mount_info.options
tags:
- CCE-80837-8
- DISA-STIG-RHEL-08-040120
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
- name: 'Add nodev Option to /dev/shm: Ensure /dev/shm is mounted with nodev option'
mount:
path: /dev/shm
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or (""
| length == 0)
tags:
- CCE-80837-8
- DISA-STIG-RHEL-08-040120
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /dev/shm)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nodev")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
fi
if mkdir -p "/dev/shm"; then
if mountpoint -q "/dev/shm"; then
mount -o remount --target "/dev/shm"
else
mount --target "/dev/shm"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Add noexec Option to /dev/shm
[ref]ruleThe noexec mount option can be used to prevent binaries
from being executed out of /dev/shm .
It can be dangerous to allow the execution of binaries
from world-writable temporary storage directories such as /dev/shm .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm . Rationale:Allowing users to execute binaries from world-writable directories
such as /dev/shm can expose the system to potential compromise. Identifiers:
CCE-80838-6 References:
11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, RHEL-08-040122, 1.1.17, SV-230510r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /dev/shm: Check information associated to mountpoint'
command: findmnt '/dev/shm'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80838-6
- DISA-STIG-RHEL-08-040122
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
- name: 'Add noexec Option to /dev/shm: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-80838-6
- DISA-STIG-RHEL-08-040122
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
- name: 'Add noexec Option to /dev/shm: If /dev/shm not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /dev/shm
- tmpfs
- tmpfs
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-80838-6
- DISA-STIG-RHEL-08-040122
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
- name: 'Add noexec Option to /dev/shm: Make sure noexec option is part of the to
/dev/shm options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "noexec" not in mount_info.options
tags:
- CCE-80838-6
- DISA-STIG-RHEL-08-040122
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
- name: 'Add noexec Option to /dev/shm: Ensure /dev/shm is mounted with noexec option'
mount:
path: /dev/shm
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or (""
| length == 0)
tags:
- CCE-80838-6
- DISA-STIG-RHEL-08-040122
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /dev/shm)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "noexec")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
fi
if mkdir -p "/dev/shm"; then
if mountpoint -q "/dev/shm"; then
mount -o remount --target "/dev/shm"
else
mount --target "/dev/shm"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Add nosuid Option to /dev/shm
[ref]ruleThe nosuid mount option can be used to prevent execution
of setuid programs in /dev/shm . The SUID and SGID permissions should not
be required in these world-writable directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm . Rationale:The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from temporary storage partitions. Identifiers:
CCE-80839-4 References:
11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, RHEL-08-040121, 1.1.16, SV-230509r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /dev/shm: Check information associated to mountpoint'
command: findmnt '/dev/shm'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80839-4
- DISA-STIG-RHEL-08-040121
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /dev/shm: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-80839-4
- DISA-STIG-RHEL-08-040121
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /dev/shm: If /dev/shm not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /dev/shm
- tmpfs
- tmpfs
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-80839-4
- DISA-STIG-RHEL-08-040121
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /dev/shm: Make sure nosuid option is part of the to
/dev/shm options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nosuid" not in mount_info.options
tags:
- CCE-80839-4
- DISA-STIG-RHEL-08-040121
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /dev/shm: Ensure /dev/shm is mounted with nosuid option'
mount:
path: /dev/shm
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or (""
| length == 0)
tags:
- CCE-80839-4
- DISA-STIG-RHEL-08-040121
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /dev/shm)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nosuid")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
fi
if mkdir -p "/dev/shm"; then
if mountpoint -q "/dev/shm"; then
mount -o remount --target "/dev/shm"
else
mount --target "/dev/shm"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Add nodev Option to /home
[ref]ruleThe nodev mount option can be used to prevent device files from
being created in /home .
Legitimate character and block devices should exist only in
the /dev directory on the root partition or within chroot
jails built for system services.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/home . Rationale:The only legitimate location for device files is the /dev directory
located on the root partition. The only exception to this is chroot jails. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nodev Option to /home: Check information associated to mountpoint'
command: findmnt --fstab '/home'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-81048-1
- configure_strategy
- high_disruption
- low_complexity
- mount_option_home_nodev
- no_reboot_needed
- unknown_severity
- name: 'Add nodev Option to /home: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-81048-1
- configure_strategy
- high_disruption
- low_complexity
- mount_option_home_nodev
- no_reboot_needed
- unknown_severity
- name: 'Add nodev Option to /home: If /home not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /home
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-81048-1
- configure_strategy
- high_disruption
- low_complexity
- mount_option_home_nodev
- no_reboot_needed
- unknown_severity
- name: 'Add nodev Option to /home: Make sure nodev option is part of the to /home
options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nodev" not in mount_info.options
tags:
- CCE-81048-1
- configure_strategy
- high_disruption
- low_complexity
- mount_option_home_nodev
- no_reboot_needed
- unknown_severity
- name: 'Add nodev Option to /home: Ensure /home is mounted with nodev option'
mount:
path: /home
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- CCE-81048-1
- configure_strategy
- high_disruption
- low_complexity
- mount_option_home_nodev
- no_reboot_needed
- unknown_severity
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/home")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/home' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /home in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /home)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " /home defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nodev")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
fi
if mkdir -p "/home"; then
if mountpoint -q "/home"; then
mount -o remount --target "/home"
else
mount --target "/home"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /home --mountoptions="nodev"
|
Add nodev Option to /tmp
[ref]ruleThe nodev mount option can be used to prevent device files from
being created in /tmp . Legitimate character and block devices
should not exist within temporary directories like /tmp .
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/tmp . Rationale:The only legitimate location for device files is the /dev directory
located on the root partition. The only exception to this is chroot jails. Identifiers:
CCE-82623-0 References:
BP28(R12), 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, RHEL-08-040123, 1.1.3, SV-230511r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nodev Option to /tmp: Check information associated to mountpoint'
command: findmnt --fstab '/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82623-0
- DISA-STIG-RHEL-08-040123
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nodev
- no_reboot_needed
- name: 'Add nodev Option to /tmp: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-82623-0
- DISA-STIG-RHEL-08-040123
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nodev
- no_reboot_needed
- name: 'Add nodev Option to /tmp: If /tmp not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /tmp
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-82623-0
- DISA-STIG-RHEL-08-040123
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nodev
- no_reboot_needed
- name: 'Add nodev Option to /tmp: Make sure nodev option is part of the to /tmp options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nodev" not in mount_info.options
tags:
- CCE-82623-0
- DISA-STIG-RHEL-08-040123
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nodev
- no_reboot_needed
- name: 'Add nodev Option to /tmp: Ensure /tmp is mounted with nodev option'
mount:
path: /tmp
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- CCE-82623-0
- DISA-STIG-RHEL-08-040123
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nodev
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " /tmp defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nodev")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
fi
if mkdir -p "/tmp"; then
if mountpoint -q "/tmp"; then
mount -o remount --target "/tmp"
else
mount --target "/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /tmp --mountoptions="nodev"
|
Add noexec Option to /tmp
[ref]ruleThe noexec mount option can be used to prevent binaries
from being executed out of /tmp .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/tmp . Rationale:Allowing users to execute binaries from world-writable directories
such as /tmp should never be necessary in normal operation and
can expose the system to potential compromise. Identifiers:
CCE-82139-7 References:
BP28(R12), 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, RHEL-08-040125, 1.1.5, SV-230513r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /tmp: Check information associated to mountpoint'
command: findmnt --fstab '/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82139-7
- DISA-STIG-RHEL-08-040125
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /tmp: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-82139-7
- DISA-STIG-RHEL-08-040125
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /tmp: If /tmp not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /tmp
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-82139-7
- DISA-STIG-RHEL-08-040125
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /tmp: Make sure noexec option is part of the to /tmp
options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "noexec" not in mount_info.options
tags:
- CCE-82139-7
- DISA-STIG-RHEL-08-040125
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /tmp: Ensure /tmp is mounted with noexec option'
mount:
path: /tmp
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- CCE-82139-7
- DISA-STIG-RHEL-08-040125
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_noexec
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " /tmp defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "noexec")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
fi
if mkdir -p "/tmp"; then
if mountpoint -q "/tmp"; then
mount -o remount --target "/tmp"
else
mount --target "/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /tmp --mountoptions="noexec"
|
Add nosuid Option to /tmp
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /tmp . The SUID and SGID permissions
should not be required in these world-writable directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/tmp . Rationale:The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from temporary storage partitions. Identifiers:
CCE-82140-5 References:
BP28(R12), 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, RHEL-08-040124, 1.1.4, SV-230512r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /tmp: Check information associated to mountpoint'
command: findmnt --fstab '/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82140-5
- DISA-STIG-RHEL-08-040124
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /tmp: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-82140-5
- DISA-STIG-RHEL-08-040124
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /tmp: If /tmp not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /tmp
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-82140-5
- DISA-STIG-RHEL-08-040124
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /tmp: Make sure nosuid option is part of the to /tmp
options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nosuid" not in mount_info.options
tags:
- CCE-82140-5
- DISA-STIG-RHEL-08-040124
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /tmp: Ensure /tmp is mounted with nosuid option'
mount:
path: /tmp
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- CCE-82140-5
- DISA-STIG-RHEL-08-040124
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_tmp_nosuid
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " /tmp defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nosuid")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
fi
if mkdir -p "/tmp"; then
if mountpoint -q "/tmp"; then
mount -o remount --target "/tmp"
else
mount --target "/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /tmp --mountoptions="nosuid"
|
Add nodev Option to /var/tmp
[ref]ruleThe nodev mount option can be used to prevent device files from
being created in /var/tmp . Legitimate character and block devices
should not exist within temporary directories like /var/tmp .
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/tmp . Rationale:The only legitimate location for device files is the /dev directory
located on the root partition. The only exception to this is chroot jails. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nodev Option to /var/tmp: Check information associated to mountpoint'
command: findmnt --fstab '/var/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82068-8
- DISA-STIG-RHEL-08-040132
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nodev
- no_reboot_needed
- name: 'Add nodev Option to /var/tmp: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-82068-8
- DISA-STIG-RHEL-08-040132
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nodev
- no_reboot_needed
- name: 'Add nodev Option to /var/tmp: If /var/tmp not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var/tmp
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-82068-8
- DISA-STIG-RHEL-08-040132
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nodev
- no_reboot_needed
- name: 'Add nodev Option to /var/tmp: Make sure nodev option is part of the to /var/tmp
options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nodev" not in mount_info.options
tags:
- CCE-82068-8
- DISA-STIG-RHEL-08-040132
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nodev
- no_reboot_needed
- name: 'Add nodev Option to /var/tmp: Ensure /var/tmp is mounted with nodev option'
mount:
path: /var/tmp
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- CCE-82068-8
- DISA-STIG-RHEL-08-040132
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nodev
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/var/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var/tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var/tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " /var/tmp defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nodev")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
fi
if mkdir -p "/var/tmp"; then
if mountpoint -q "/var/tmp"; then
mount -o remount --target "/var/tmp"
else
mount --target "/var/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/tmp --mountoptions="nodev"
|
Add noexec Option to /var/tmp
[ref]ruleThe noexec mount option can be used to prevent binaries
from being executed out of /var/tmp .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/tmp . Rationale:Allowing users to execute binaries from world-writable directories
such as /var/tmp should never be necessary in normal operation and
can expose the system to potential compromise. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /var/tmp: Check information associated to mountpoint'
command: findmnt --fstab '/var/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82151-2
- DISA-STIG-RHEL-08-040134
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/tmp: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-82151-2
- DISA-STIG-RHEL-08-040134
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/tmp: If /var/tmp not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var/tmp
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-82151-2
- DISA-STIG-RHEL-08-040134
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/tmp: Make sure noexec option is part of the to
/var/tmp options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "noexec" not in mount_info.options
tags:
- CCE-82151-2
- DISA-STIG-RHEL-08-040134
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/tmp: Ensure /var/tmp is mounted with noexec option'
mount:
path: /var/tmp
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- CCE-82151-2
- DISA-STIG-RHEL-08-040134
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/var/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var/tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var/tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " /var/tmp defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "noexec")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
fi
if mkdir -p "/var/tmp"; then
if mountpoint -q "/var/tmp"; then
mount -o remount --target "/var/tmp"
else
mount --target "/var/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/tmp --mountoptions="noexec"
|
Add nosuid Option to /var/tmp
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /var/tmp . The SUID and SGID permissions
should not be required in these world-writable directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/tmp . Rationale:The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from temporary storage partitions. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /var/tmp: Check information associated to mountpoint'
command: findmnt --fstab '/var/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82154-6
- DISA-STIG-RHEL-08-040133
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/tmp: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-82154-6
- DISA-STIG-RHEL-08-040133
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/tmp: If /var/tmp not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var/tmp
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-82154-6
- DISA-STIG-RHEL-08-040133
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/tmp: Make sure nosuid option is part of the to
/var/tmp options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nosuid" not in mount_info.options
tags:
- CCE-82154-6
- DISA-STIG-RHEL-08-040133
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/tmp: Ensure /var/tmp is mounted with nosuid option'
mount:
path: /var/tmp
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- CCE-82154-6
- DISA-STIG-RHEL-08-040133
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/var/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var/tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var/tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " /var/tmp defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nosuid")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
fi
if mkdir -p "/var/tmp"; then
if mountpoint -q "/var/tmp"; then
mount -o remount --target "/var/tmp"
else
mount --target "/var/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/tmp --mountoptions="nosuid"
|
Restrict Programs from Dangerous Execution Patterns
[ref]groupThe recommendations in this section are designed to
ensure that the system's features to protect against potentially
dangerous program execution are activated.
These protections are applied at the system initialization or
kernel level, and defend against certain types of badly-configured
or compromised programs. |
contains 5 rules |
Disable Core Dumps
[ref]groupA core dump file is the memory image of an executable
program when it was terminated by the operating system due to
errant behavior. In most cases, only software developers
legitimately need to access these files. The core dump files may
also contain sensitive information, or unnecessarily occupy large
amounts of disk space.
Once a hard limit is set in /etc/security/limits.conf , or
to a file within the /etc/security/limits.d/ directory, a
user cannot increase that limit within his or her own session. If access
to core dumps is required, consider restricting them to only
certain users or groups. See the limits.conf man page for more
information.
The core dumps of setuid programs are further protected. The
sysctl variable fs.suid_dumpable controls whether
the kernel allows core dumps from these programs at all. The default
value of 0 is recommended. |
contains 4 rules |
Disable core dump backtraces
[ref]ruleThe ProcessSizeMax option in [Coredump] section
of /etc/systemd/coredump.conf
specifies the maximum size in bytes of a core which will be processed.
Core dumps exceeding this size may be stored, but the backtrace will not
be generated. Warning:
If the /etc/systemd/coredump.conf file
does not already contain the [Coredump] section,
the value will not be configured correctly. Rationale:A core dump includes a memory image taken at the time the operating system
terminates an application. The memory image could contain sensitive data
and is generally useful only for developers or system operators trying to
debug problems.
Enabling core dumps on production systems is not recommended,
however there may be overriding operational requirements to enable advanced
debuging. Permitting temporary enablement of core dumps during such situations
should be reviewed through local needs and policy. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable core dump backtraces
block:
- name: Check for duplicate values
lineinfile:
path: /etc/systemd/coredump.conf
create: false
regexp: ^\s*ProcessSizeMax\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/systemd/coredump.conf
lineinfile:
path: /etc/systemd/coredump.conf
create: false
regexp: ^\s*ProcessSizeMax\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/systemd/coredump.conf
lineinfile:
path: /etc/systemd/coredump.conf
create: false
regexp: ^\s*ProcessSizeMax\s*=\s*
line: ProcessSizeMax=0
state: present
tags:
- CCE-82251-0
- DISA-STIG-RHEL-08-010675
- NIST-800-53-CM-6
- coredump_disable_backtraces
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
if [ -e "/etc/systemd/coredump.conf" ] ; then
LC_ALL=C sed -i "/^\s*ProcessSizeMax\s*=\s*/Id" "/etc/systemd/coredump.conf"
else
touch "/etc/systemd/coredump.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/coredump.conf"
cp "/etc/systemd/coredump.conf" "/etc/systemd/coredump.conf.bak"
# Insert at the end of the file
printf '%s\n' "ProcessSizeMax=0" >> "/etc/systemd/coredump.conf"
# Clean up after ourselves.
rm "/etc/systemd/coredump.conf.bak"
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,%23%20%20This%20file%20is%20part%20of%20systemd.%0A%23%0A%23%20%20systemd%20is%20free%20software%3B%20you%20can%20redistribute%20it%20and/or%20modify%20it%0A%23%20%20under%20the%20terms%20of%20the%20GNU%20Lesser%20General%20Public%20License%20as%20published%20by%0A%23%20%20the%20Free%20Software%20Foundation%3B%20either%20version%202.1%20of%20the%20License%2C%20or%0A%23%20%20%28at%20your%20option%29%20any%20later%20version.%0A%23%0A%23%20Entries%20in%20this%20file%20show%20the%20compile%20time%20defaults.%0A%23%20You%20can%20change%20settings%20by%20editing%20this%20file.%0A%23%20Defaults%20can%20be%20restored%20by%20simply%20deleting%20this%20file.%0A%23%0A%23%20See%20coredump.conf%285%29%20for%20details.%0A%0A%5BCoredump%5D%0A%23Storage%3Dexternal%0A%23Compress%3Dyes%0A%23ProcessSizeMax%3D2G%0A%23ExternalSizeMax%3D2G%0A%23JournalSizeMax%3D767M%0A%23MaxUse%3D%0A%23KeepFree%3D%0AStorage%3Dnone%0AProcessSizeMax%3D0%0A
mode: 0644
path: /etc/systemd/coredump.conf
overwrite: true
|
Disable storing core dump
[ref]ruleThe Storage option in [Coredump] section
of /etc/systemd/coredump.conf
can be set to none to disable storing core dumps permanently. Warning:
If the /etc/systemd/coredump.conf file
does not already contain the [Coredump] section,
the value will not be configured correctly. Rationale:A core dump includes a memory image taken at the time the operating system
terminates an application. The memory image could contain sensitive data
and is generally useful only for developers or system operators trying to
debug problems. Enabling core dumps on production systems is not recommended,
however there may be overriding operational requirements to enable advanced
debuging. Permitting temporary enablement of core dumps during such situations
should be reviewed through local needs and policy. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable storing core dump
block:
- name: Check for duplicate values
lineinfile:
path: /etc/systemd/coredump.conf
create: false
regexp: ^\s*Storage\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/systemd/coredump.conf
lineinfile:
path: /etc/systemd/coredump.conf
create: false
regexp: ^\s*Storage\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/systemd/coredump.conf
lineinfile:
path: /etc/systemd/coredump.conf
create: false
regexp: ^\s*Storage\s*=\s*
line: Storage=none
state: present
tags:
- CCE-82252-8
- DISA-STIG-RHEL-08-010674
- NIST-800-53-CM-6
- coredump_disable_storage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
if [ -e "/etc/systemd/coredump.conf" ] ; then
LC_ALL=C sed -i "/^\s*Storage\s*=\s*/Id" "/etc/systemd/coredump.conf"
else
touch "/etc/systemd/coredump.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/coredump.conf"
cp "/etc/systemd/coredump.conf" "/etc/systemd/coredump.conf.bak"
# Insert at the end of the file
printf '%s\n' "Storage=none" >> "/etc/systemd/coredump.conf"
# Clean up after ourselves.
rm "/etc/systemd/coredump.conf.bak"
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,%23%20%20This%20file%20is%20part%20of%20systemd.%0A%23%0A%23%20%20systemd%20is%20free%20software%3B%20you%20can%20redistribute%20it%20and/or%20modify%20it%0A%23%20%20under%20the%20terms%20of%20the%20GNU%20Lesser%20General%20Public%20License%20as%20published%20by%0A%23%20%20the%20Free%20Software%20Foundation%3B%20either%20version%202.1%20of%20the%20License%2C%20or%0A%23%20%20%28at%20your%20option%29%20any%20later%20version.%0A%23%0A%23%20Entries%20in%20this%20file%20show%20the%20compile%20time%20defaults.%0A%23%20You%20can%20change%20settings%20by%20editing%20this%20file.%0A%23%20Defaults%20can%20be%20restored%20by%20simply%20deleting%20this%20file.%0A%23%0A%23%20See%20coredump.conf%285%29%20for%20details.%0A%0A%5BCoredump%5D%0A%23Storage%3Dexternal%0A%23Compress%3Dyes%0A%23ProcessSizeMax%3D2G%0A%23ExternalSizeMax%3D2G%0A%23JournalSizeMax%3D767M%0A%23MaxUse%3D%0A%23KeepFree%3D%0AStorage%3Dnone%0AProcessSizeMax%3D0%0A
mode: 0644
path: /etc/systemd/coredump.conf
overwrite: true
|
Disable Core Dumps for All Users
[ref]ruleTo disable core dumps for all users, add the following line to
/etc/security/limits.conf , or to a file within the
/etc/security/limits.d/ directory:
* hard core 0 Rationale:A core dump includes a memory image taken at the time the operating system
terminates an application. The memory image could contain sensitive data and is generally useful
only for developers trying to debug problems. Identifiers:
CCE-81038-2 References:
1, 12, 13, 15, 16, 2, 7, 8, APO13.01, BAI04.04, DSS01.03, DSS03.05, DSS05.07, CCI-000366, SR 6.2, SR 7.1, SR 7.2, A.12.1.3, A.17.2.1, CM-6, SC-7(10), DE.CM-1, PR.DS-4, SRG-OS-000480-GPOS-00227, RHEL-08-010673, 1.6.1, SV-230313r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-81038-2
- DISA-STIG-RHEL-08-010673
- NIST-800-53-CM-6
- NIST-800-53-SC-7(10)
- disable_users_coredumps
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: disable core dumps with limits
lineinfile:
dest: /etc/security/limits.conf
regexp: ^[^#].*core
line: '* hard core 0'
create: true
when: '"pam" in ansible_facts.packages'
tags:
- CCE-81038-2
- DISA-STIG-RHEL-08-010673
- NIST-800-53-CM-6
- NIST-800-53-SC-7(10)
- disable_users_coredumps
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
SECURITY_LIMITS_FILE="/etc/security/limits.conf"
if grep -qE '^\s*\*\s+hard\s+core' $SECURITY_LIMITS_FILE; then
sed -ri 's/(hard\s+core\s+)[[:digit:]]+/\1 0/' $SECURITY_LIMITS_FILE
else
echo "* hard core 0" >> $SECURITY_LIMITS_FILE
fi
if ls /etc/security/limits.d/*.conf > /dev/null; then
sed -ri '/^\s*\*\s+hard\s+core/d' /etc/security/limits.d/*.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,%2A%20%20%20%20%20hard%20%20%20core%20%20%20%200
mode: 0644
path: /etc/security/limits.d/75-disable_users_coredumps.conf
overwrite: true
|
Disable Core Dumps for SUID programs
[ref]ruleTo set the runtime status of the fs.suid_dumpable kernel parameter, run the following command: $ sudo sysctl -w fs.suid_dumpable=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : fs.suid_dumpable = 0 Rationale:The core dump of a setuid program is more likely to contain
sensitive data, as the program itself runs with greater privileges than the
user who initiated execution of the program. Disabling the ability for any
setuid program to write a core file decreases the risk of unauthorized access
of such data. Identifiers:
CCE-80912-9 References:
BP28(R23), 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SI-11(a), SI-11(b), 1.6.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*fs.suid_dumpable.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80912-9
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
- name: Comment out any occurrences of fs.suid_dumpable from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*fs.suid_dumpable
replace: '#fs.suid_dumpable'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80912-9
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
- name: Ensure sysctl fs.suid_dumpable is set to 0
sysctl:
name: fs.suid_dumpable
value: '0'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80912-9
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of fs.suid_dumpable from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*fs.suid_dumpable.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "fs.suid_dumpable" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for fs.suid_dumpable
#
/sbin/sysctl -q -n -w fs.suid_dumpable="0"
#
# If fs.suid_dumpable present in /etc/sysctl.conf, change value to "0"
# else, add "fs.suid_dumpable = 0" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.suid_dumpable")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^fs.suid_dumpable\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^fs.suid_dumpable\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80912-9"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable ExecShield
[ref]groupExecShield describes kernel features that provide
protection against exploitation of memory corruption errors such as buffer
overflows. These features include random placement of the stack and other
memory regions, prevention of execution in memory that should only hold data,
and special handling of text buffers. These protections are enabled by default
on 32-bit systems and controlled through sysctl variables
kernel.exec-shield and kernel.randomize_va_space . On the latest
64-bit systems, kernel.exec-shield cannot be enabled or disabled with
sysctl . |
contains 1 rule |
Enable Randomized Layout of Virtual Address Space
[ref]ruleTo set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command: $ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.randomize_va_space = 2 Rationale:Address space layout randomization (ASLR) makes it more difficult for an
attacker to predict the location of attack code they have introduced into a
process's address space during an attempt at exploitation. Additionally,
ASLR makes it more difficult for an attacker to know the location of
existing code in order to re-purpose it using return oriented programming
(ROP) techniques. Identifiers:
CCE-80916-0 References:
BP28(R23), 3.1.7, CCI-000366, CCI-002824, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), CIP-002-5 R1.1, CIP-002-5 R1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 4.1, CIP-004-6 4.2, CIP-004-6 R2.2.3, CIP-004-6 R2.2.4, CIP-004-6 R2.3, CIP-004-6 R4, CIP-005-6 R1, CIP-005-6 R1.1, CIP-005-6 R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-6 R.1.1, CIP-009-6 R4, SC-30, SC-30(2), CM-6(a), SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227, RHEL-08-010430, 1.6.2, SV-230280r818831_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /etc/sysctl.d/
- /run/sysctl.d/
contains: ^[\s]*kernel.randomize_va_space.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80916-0
- DISA-STIG-RHEL-08-010430
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
- name: Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*kernel.randomize_va_space
replace: '#kernel.randomize_va_space'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80916-0
- DISA-STIG-RHEL-08-010430
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
- name: Ensure sysctl kernel.randomize_va_space is set to 2
sysctl:
name: kernel.randomize_va_space
value: '2'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80916-0
- DISA-STIG-RHEL-08-010430
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*kernel.randomize_va_space.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "kernel.randomize_va_space" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for kernel.randomize_va_space
#
/sbin/sysctl -q -n -w kernel.randomize_va_space="2"
#
# If kernel.randomize_va_space present in /etc/sysctl.conf, change value to "2"
# else, add "kernel.randomize_va_space = 2" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.randomize_va_space")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "2"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.randomize_va_space\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^kernel.randomize_va_space\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-80916-0"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,kernel.randomize_va_space%3D2%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_kernel_randomize_va_space.conf
overwrite: true
|
SELinux
[ref]groupSELinux is a feature of the Linux kernel which can be
used to guard against misconfigured or compromised programs.
SELinux enforces the idea that programs should be limited in what
files they can access and what actions they can take.
The default SELinux policy, as configured on Red Hat Enterprise Linux 8, has been
sufficiently developed and debugged that it should be usable on
almost any system with minimal configuration and a small
amount of system administrator training. This policy prevents
system services - including most of the common network-visible
services such as mail servers, FTP servers, and DNS servers - from
accessing files which those services have no valid reason to
access. This action alone prevents a huge amount of possible damage
from network attacks against services, from trojaned software, and
so forth.
This guide recommends that SELinux be enabled using the
default (targeted) policy on every Red Hat Enterprise Linux 8 system, unless that
system has unusual requirements which make a stronger policy
appropriate.
For more information on SELinux, see https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/using_selinux. |
contains 6 rules |
Install libselinux Package
[ref]ruleThe libselinux package can be installed with the following command:
$ sudo yum install libselinux Rationale:Security-enhanced Linux is a feature of the Linux kernel and a number of utilities
with enhanced security functionality designed to add mandatory access controls to Linux.
The libselinux package contains the core library of the Security-enhanced Linux system. Identifiers:
CCE-82877-2 References:
1.7.1.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure libselinux is installed
package:
name: libselinux
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82877-2
- enable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_libselinux_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "libselinux" ; then
yum install -y "libselinux"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
package --add=libselinux
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_libselinux
class install_libselinux {
package { 'libselinux':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "libselinux"
version = "*"
|
Uninstall mcstrans Package
[ref]ruleThe mcstransd daemon provides category label information
to client processes requesting information. The label translations are defined
in /etc/selinux/targeted/setrans.conf .
The mcstrans package can be removed with the following command:
$ sudo yum erase mcstrans Rationale:Since this service is not used very often, disable it to reduce the
amount of potentially vulnerable code running on the system. Identifiers:
CCE-82756-8 References:
1.7.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure mcstrans is removed
package:
name: mcstrans
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82756-8
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_mcstrans_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# CAUTION: This remediation script will remove mcstrans
# from the system, and may remove any packages
# that depend on mcstrans. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "mcstrans" ; then
yum remove -y "mcstrans"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=mcstrans
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_mcstrans
class remove_mcstrans {
package { 'mcstrans':
ensure => 'purged',
}
}
|
Ensure SELinux Not Disabled in /etc/default/grub
[ref]ruleSELinux can be disabled at boot time by an argument in
/etc/default/grub .
Remove any instances of selinux=0 from the kernel arguments in that
file to prevent SELinux from being disabled at boot. Rationale:Disabling a major host protection feature, such as SELinux, at boot time prevents
it from confining system services at boot time. Further, it increases
the chances that it will remain off during system operation. Identifiers:
CCE-80827-9 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-000022, CCI-000032, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-3, AC-3(3)(a), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-VMM-001780, 1.7.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Find /etc/grub.d/ files
find:
paths:
- /etc/grub.d/
follow: true
register: grub
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80827-9
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure SELinux Not Disabled in grub files
replace:
dest: '{{ item.path }}'
regexp: (selinux|enforcing)=0
with_items:
- '{{ grub.files }}'
- path: /etc/grub2.cfg
- path: /etc/default/grub
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80827-9
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sed -i --follow-symlinks "s/selinux=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*
sed -i --follow-symlinks "s/enforcing=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure No Daemons are Unconfined by SELinux
[ref]ruleDaemons for which the SELinux policy does not contain rules will inherit the
context of the parent process. Because daemons are launched during
startup and descend from the init process, they inherit the unconfined_service_t context.
To check for unconfined daemons, run the following command:
$ sudo ps -eZ | grep "unconfined_service_t"
It should produce no output in a well-configured system.Warning:
Automatic remediation of this control is not available. Remediation
can be achieved by amending SELinux policy or stopping the unconfined
daemons as outlined above. Rationale:Daemons which run with the unconfined_service_t context may cause AVC denials,
or allow privileges that the daemon does not require. Identifiers:
CCE-80867-5 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, MEA02.01, 3.1.2, 3.1.5, 3.7.2, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-3(3)(a), AC-6, PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, PR.PT-3, 1.7.1.5 |
Configure SELinux Policy
[ref]ruleThe SELinux targeted policy is appropriate for
general-purpose desktops and servers, as well as systems in many other roles.
To configure the system to use this policy, add or correct the following line
in /etc/selinux/config :
SELINUXTYPE=targeted
Other policies, such as mls , provide additional security labeling
and greater confinement but are not compatible with many general-purpose
use cases.Rationale:Setting the SELinux policy to targeted or a more specialized policy
ensures the system will confine processes that are likely to be
targeted for exploitation, such as network or system services.
Note: During the development or debugging of SELinux modules, it is common to
temporarily place non-production systems in permissive mode. In such
temporary cases, SELinux policies should be developed, and once work
is completed, the system should be reconfigured to
targeted . Identifiers:
CCE-80868-3 References:
BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000445-VMM-001780, RHEL-08-010450, 1.7.1.3, SV-230282r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_selinux_policy_name # promote to variable
set_fact:
var_selinux_policy_name: !!str targeted
tags:
- always
- name: Configure SELinux Policy
block:
- name: Check for duplicate values
lineinfile:
path: /etc/selinux/config
create: false
regexp: ^SELINUXTYPE=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: false
regexp: ^SELINUXTYPE=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUXTYPE=
line: SELINUXTYPE={{ var_selinux_policy_name }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80868-3
- DISA-STIG-RHEL-08-010450
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- NIST-800-53-AU-9
- NIST-800-53-SC-7(21)
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- selinux_policytype
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_selinux_policy_name='targeted'
if [ -e "/etc/selinux/config" ] ; then
LC_ALL=C sed -i "/^SELINUXTYPE=/Id" "/etc/selinux/config"
else
touch "/etc/selinux/config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/selinux/config"
cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUXTYPE=$var_selinux_policy_name" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure SELinux State is Enforcing
[ref]ruleThe SELinux state should be set to enforcing at
system boot time. In the file /etc/selinux/config , add or correct the
following line to configure the system to boot into enforcing mode:
SELINUX=enforcing Rationale:Setting the SELinux state to enforcing ensures SELinux is able to confine
potentially compromised processes to the security policy, which is designed to
prevent them from causing damage to the system or further elevating their
privileges. Identifiers:
CCE-80869-1 References:
BP28(R4), BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000134-GPOS-00068, SRG-OS-000445-VMM-001780, RHEL-08-010170, 1.7.1.4, SV-230240r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_selinux_state # promote to variable
set_fact:
var_selinux_state: !!str enforcing
tags:
- always
- name: Ensure SELinux State is Enforcing
block:
- name: Check for duplicate values
lineinfile:
path: /etc/selinux/config
create: false
regexp: ^SELINUX=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: false
regexp: ^SELINUX=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUX=
line: SELINUX={{ var_selinux_state }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80869-1
- DISA-STIG-RHEL-08-010170
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- NIST-800-53-AU-9
- NIST-800-53-SC-7(21)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- selinux_state
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_selinux_state='enforcing'
if [ -e "/etc/selinux/config" ] ; then
LC_ALL=C sed -i "/^SELINUX=/Id" "/etc/selinux/config"
else
touch "/etc/selinux/config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/selinux/config"
cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUX=$var_selinux_state" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"
fixfiles onboot
fixfiles -f relabel
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Services
[ref]groupThe best protection against vulnerable software is running less software. This section describes how to review
the software which Red Hat Enterprise Linux 8 installs on a system and disable software which is not needed. It
then enumerates the software packages installed on a default Red Hat Enterprise Linux 8 system and provides guidance about which
ones can be safely disabled.
Red Hat Enterprise Linux 8 provides a convenient minimal install option that essentially installs the bare necessities for a functional
system. When building Red Hat Enterprise Linux 8 systems, it is highly recommended to select the minimal packages and then build up
the system from there. |
contains 68 rules |
Avahi Server
[ref]groupThe Avahi daemon implements the DNS Service Discovery
and Multicast DNS protocols, which provide service and host
discovery on a network. It allows a system to automatically
identify resources on the network, such as printers or web servers.
This capability is also known as mDNSresponder and is a major part
of Zeroconf networking. |
contains 1 rule |
Disable Avahi Server if Possible
[ref]groupBecause the Avahi daemon service keeps an open network
port, it is subject to network attacks.
Disabling it can reduce the system's vulnerability to such attacks. |
contains 1 rule |
Disable Avahi Server Software
[ref]rule
The avahi-daemon service can be disabled with the following command:
$ sudo systemctl mask --now avahi-daemon.service Rationale:Because the Avahi daemon service keeps an open network
port, it is subject to network attacks. Its functionality
is convenient but is only appropriate if the local network
can be trusted. Identifiers:
CCE-82188-4 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service avahi-daemon
block:
- name: Disable service avahi-daemon
systemd:
name: avahi-daemon.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82188-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
- name: Unit Socket Exists - avahi-daemon.socket
command: systemctl list-unit-files avahi-daemon.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82188-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
- name: Disable socket avahi-daemon
systemd:
name: avahi-daemon.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"avahi-daemon.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82188-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'avahi-daemon.service'
"$SYSTEMCTL_EXEC" disable 'avahi-daemon.service'
"$SYSTEMCTL_EXEC" mask 'avahi-daemon.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^avahi-daemon.socket'; then
"$SYSTEMCTL_EXEC" stop 'avahi-daemon.socket'
"$SYSTEMCTL_EXEC" mask 'avahi-daemon.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'avahi-daemon.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: avahi-daemon.service
enabled: false
mask: true
- name: avahi-daemon.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_avahi-daemon
class disable_avahi-daemon {
service {'avahi-daemon':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["avahi-daemon"]
|
Cron and At Daemons
[ref]groupThe cron and at services are used to allow commands to
be executed at a later time. The cron service is required by almost
all systems to perform necessary maintenance tasks, while at may or
may not be required on a given system. Both daemons should be
configured defensively. |
contains 26 rules |
Restrict at and cron to Authorized Users if Necessary
[ref]groupThe /etc/cron.allow and /etc/at.allow files contain lists of
users who are allowed to use cron and at to delay execution of
processes. If these files exist and if the corresponding files
/etc/cron.deny and /etc/at.deny do not exist, then only users
listed in the relevant allow files can run the crontab and at commands
to submit jobs to be run at scheduled intervals. On many systems, only the
system administrator needs the ability to schedule jobs. Note that even if a
given user is not listed in cron.allow , cron jobs can still be run as
that user. The cron.allow file controls only administrative access
to the crontab command for scheduling and modifying cron jobs.
To restrict at and cron to only authorized users:
- Remove the
cron.deny file:$ sudo rm /etc/cron.deny - Edit
/etc/cron.allow , adding one line for each user allowed to use
the crontab command to create cron jobs. - Remove the
at.deny file:$ sudo rm /etc/at.deny - Edit
/etc/at.allow , adding one line for each user allowed to use
the at command to create at jobs.
|
contains 7 rules |
Ensure that /etc/at.deny does not exist
[ref]ruleThe file /etc/at.deny should not exist.
Use /etc/at.allow instead. Rationale:Access to at should be restricted.
It is easier to manage an allow list than a deny list. Identifiers:
CCE-86945-3 References:
5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Remove /etc/at.deny
file:
path: /etc/at.deny
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86945-3
- disable_strategy
- file_at_deny_not_exist
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
#!/bin/bash
if [[ -f /etc/at.deny ]]; then
rm /etc/at.deny
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure that /etc/cron.deny does not exist
[ref]ruleThe file /etc/cron.deny should not exist.
Use /etc/cron.allow instead. Rationale:Access to cron should be restricted.
It is easier to manage an allow list than a deny list. Identifiers:
CCE-86849-7 References:
5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Remove /etc/cron.deny
file:
path: /etc/cron.deny
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86849-7
- disable_strategy
- file_cron_deny_not_exist
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
#!/bin/bash
if [[ -f /etc/cron.deny ]]; then
rm /etc/cron.deny
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns /etc/at.allow file
[ref]ruleIf /etc/at.allow exists, it must be group-owned by root .
To properly set the group owner of /etc/at.allow , run the command:
$ sudo chgrp root /etc/at.allow Rationale:If the owner of the at.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information. Identifiers:
CCE-87102-0 References:
5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/at.allow
stat:
path: /etc/at.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-87102-0
- configure_strategy
- file_groupowner_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/at.allow
file:
path: /etc/at.allow
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-87102-0
- configure_strategy
- file_groupowner_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /etc/at.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns /etc/cron.allow file
[ref]ruleIf /etc/cron.allow exists, it must be group-owned by root .
To properly set the group owner of /etc/cron.allow , run the command:
$ sudo chgrp root /etc/cron.allow Rationale:If the owner of the cron.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information. Identifiers:
CCE-86829-9 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/cron.allow
stat:
path: /etc/cron.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86829-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/cron.allow
file:
path: /etc/cron.allow
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-86829-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /etc/cron.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify User Who Owns /etc/cron.allow file
[ref]ruleIf /etc/cron.allow exists, it must be owned by root .
To properly set the owner of /etc/cron.allow , run the command:
$ sudo chown root /etc/cron.allow Rationale:If the owner of the cron.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information. Identifiers:
CCE-86843-0 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/cron.allow
stat:
path: /etc/cron.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86843-0
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/cron.allow
file:
path: /etc/cron.allow
owner: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-86843-0
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chown 0 /etc/cron.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on /etc/at.allow file
[ref]ruleIf /etc/at.allow exists, it must have permissions 0600
or more restrictive.
To properly set the permissions of /etc/at.allow , run the command:
$ sudo chmod /etc/at.allow Rationale:If the permissions of the at.allow file are not set to 0600 or more restrictive,
the possibility exists for an unauthorized user to view or edit sensitive information. Identifiers:
CCE-86903-2 References:
5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/at.allow
stat:
path: /etc/at.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86903-2
- configure_strategy
- file_permissions_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /etc/at.allow
file:
path: /etc/at.allow
mode: u-xs,g-xwrs,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-86903-2
- configure_strategy
- file_permissions_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xwrs,o-xwrt /etc/at.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on /etc/cron.allow file
[ref]ruleIf /etc/cron.allow exists, it must have permissions 0600
or more restrictive.
To properly set the permissions of /etc/cron.allow , run the command:
$ sudo chmod /etc/cron.allow Rationale:If the permissions of the cron.allow file are not set to 0600 or more restrictive,
the possibility exists for an unauthorized user to view or edit sensitive information. Identifiers:
CCE-86876-0 References:
5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/cron.allow
stat:
path: /etc/cron.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86876-0
- configure_strategy
- file_permissions_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /etc/cron.allow
file:
path: /etc/cron.allow
mode: u-xs,g-xwrs,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-86876-0
- configure_strategy
- file_permissions_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xwrs,o-xwrt /etc/cron.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable cron Service
[ref]ruleThe crond service is used to execute commands at
preconfigured times. It is required by almost all systems to perform necessary
maintenance tasks, such as notifying root of system activity.
The crond service can be enabled with the following command:
$ sudo systemctl enable crond.service Rationale:Due to its usage for maintenance and security-supporting tasks,
enabling the cron daemon is essential. Identifiers:
CCE-80875-8 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-6(a), PR.IP-1, PR.PT-3, 5.1.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Enable service crond
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service crond
service:
name: crond
enabled: 'yes'
state: started
masked: 'no'
when:
- '"cronie" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80875-8
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_crond_enabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'crond.service'
"$SYSTEMCTL_EXEC" start 'crond.service'
"$SYSTEMCTL_EXEC" enable 'crond.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include enable_crond
class enable_crond {
service {'crond':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["crond"]
|
Verify Group Who Owns cron.d
[ref]rule
To properly set the group owner of /etc/cron.d , run the command:
$ sudo chgrp root /etc/cron.d Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82268-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.d/
file:
path: /etc/cron.d/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82268-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_cron_d
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.d/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.daily
[ref]rule
To properly set the group owner of /etc/cron.daily , run the command:
$ sudo chgrp root /etc/cron.daily Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82234-6 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.daily/
file:
path: /etc/cron.daily/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82234-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_cron_daily
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.daily/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.hourly
[ref]rule
To properly set the group owner of /etc/cron.hourly , run the command:
$ sudo chgrp root /etc/cron.hourly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82227-0 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.hourly/
file:
path: /etc/cron.hourly/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82227-0
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_cron_hourly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.hourly/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.monthly
[ref]rule
To properly set the group owner of /etc/cron.monthly , run the command:
$ sudo chgrp root /etc/cron.monthly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82256-9 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.monthly/
file:
path: /etc/cron.monthly/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82256-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_cron_monthly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.monthly/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.weekly
[ref]rule
To properly set the group owner of /etc/cron.weekly , run the command:
$ sudo chgrp root /etc/cron.weekly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82244-5 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.weekly/
file:
path: /etc/cron.weekly/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82244-5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_cron_weekly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.weekly/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns Crontab
[ref]rule
To properly set the group owner of /etc/crontab , run the command:
$ sudo chgrp root /etc/crontab Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82223-9 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/crontab
stat:
path: /etc/crontab
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82223-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/crontab
file:
path: /etc/crontab
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-82223-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /etc/crontab
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.d
[ref]rule
To properly set the owner of /etc/cron.d , run the command:
$ sudo chown root /etc/cron.d Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-82272-6 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.d/
file:
path: /etc/cron.d/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82272-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_d
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.d/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.daily
[ref]rule
To properly set the owner of /etc/cron.daily , run the command:
$ sudo chown root /etc/cron.daily Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-82237-9 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.daily/
file:
path: /etc/cron.daily/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82237-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_daily
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.daily/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.hourly
[ref]rule
To properly set the owner of /etc/cron.hourly , run the command:
$ sudo chown root /etc/cron.hourly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-82209-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.hourly/
file:
path: /etc/cron.hourly/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82209-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_hourly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.hourly/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.monthly
[ref]rule
To properly set the owner of /etc/cron.monthly , run the command:
$ sudo chown root /etc/cron.monthly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-82260-1 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.monthly/
file:
path: /etc/cron.monthly/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82260-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_monthly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.monthly/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.weekly
[ref]rule
To properly set the owner of /etc/cron.weekly , run the command:
$ sudo chown root /etc/cron.weekly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-82247-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.weekly/
file:
path: /etc/cron.weekly/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82247-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_weekly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.weekly/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on crontab
[ref]rule
To properly set the owner of /etc/crontab , run the command:
$ sudo chown root /etc/crontab Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-82224-7 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/crontab
stat:
path: /etc/crontab
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82224-7
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/crontab
file:
path: /etc/crontab
owner: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-82224-7
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chown 0 /etc/crontab
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.d
[ref]rule
To properly set the permissions of /etc/cron.d , run the command:
$ sudo chmod 0700 /etc/cron.d Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-82277-5 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Set permissions for /etc/cron.d/
file:
path: /etc/cron.d/
state: directory
mode: u-s,g-xwrs,o-xwrt
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82277-5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_cron_d
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.d/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.daily
[ref]rule
To properly set the permissions of /etc/cron.daily , run the command:
$ sudo chmod 0700 /etc/cron.daily Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-82240-3 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Set permissions for /etc/cron.daily/
file:
path: /etc/cron.daily/
state: directory
mode: u-s,g-xwrs,o-xwrt
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82240-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_cron_daily
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.daily/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.hourly
[ref]rule
To properly set the permissions of /etc/cron.hourly , run the command:
$ sudo chmod 0700 /etc/cron.hourly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-82230-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Set permissions for /etc/cron.hourly/
file:
path: /etc/cron.hourly/
state: directory
mode: u-s,g-xwrs,o-xwrt
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82230-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_cron_hourly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.hourly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.monthly
[ref]rule
To properly set the permissions of /etc/cron.monthly , run the command:
$ sudo chmod 0700 /etc/cron.monthly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-82263-5 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Set permissions for /etc/cron.monthly/
file:
path: /etc/cron.monthly/
state: directory
mode: u-s,g-xwrs,o-xwrt
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82263-5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_cron_monthly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.monthly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.weekly
[ref]rule
To properly set the permissions of /etc/cron.weekly , run the command:
$ sudo chmod 0700 /etc/cron.weekly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-82253-6 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Set permissions for /etc/cron.weekly/
file:
path: /etc/cron.weekly/
state: directory
mode: u-s,g-xwrs,o-xwrt
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82253-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_cron_weekly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.weekly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on crontab
[ref]rule
To properly set the permissions of /etc/crontab , run the command:
$ sudo chmod 0600 /etc/crontab Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-82206-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/crontab
stat:
path: /etc/crontab
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82206-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /etc/crontab
file:
path: /etc/crontab
mode: u-xs,g-xwrs,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-82206-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xwrs,o-xwrt /etc/crontab
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
The Dynamic Host Configuration Protocol (DHCP) allows
systems to request and obtain an IP address and other configuration
parameters from a server.
This guide recommends configuring networking on clients by manually editing
the appropriate files under /etc/sysconfig . Use of DHCP can make client
systems vulnerable to compromise by rogue DHCP servers, and should be avoided
unless necessary. If using DHCP is necessary, however, there are best practices
that should be followed to minimize security risk. |
contains 1 rule |
Disable DHCP Server
[ref]groupThe DHCP server dhcpd is not installed or activated by
default. If the software was installed and activated, but the
system does not need to act as a DHCP server, it should be disabled
and removed. |
contains 1 rule |
Disable DHCP Service
[ref]ruleThe dhcpd service should be disabled on
any system that does not need to act as a DHCP server.
The dhcpd service can be disabled with the following command:
$ sudo systemctl mask --now dhcpd.service Rationale:Unmanaged or unintentionally activated DHCP servers may provide faulty information
to clients, interfering with the operation of a legitimate site
DHCP server if there is one. Identifiers:
CCE-82864-0 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.15 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service dhcpd
block:
- name: Disable service dhcpd
systemd:
name: dhcpd.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82864-0
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_dhcpd_disabled
- name: Unit Socket Exists - dhcpd.socket
command: systemctl list-unit-files dhcpd.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82864-0
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_dhcpd_disabled
- name: Disable socket dhcpd
systemd:
name: dhcpd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"dhcpd.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82864-0
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_dhcpd_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'dhcpd.service'
"$SYSTEMCTL_EXEC" disable 'dhcpd.service'
"$SYSTEMCTL_EXEC" mask 'dhcpd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^dhcpd.socket'; then
"$SYSTEMCTL_EXEC" stop 'dhcpd.socket'
"$SYSTEMCTL_EXEC" mask 'dhcpd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'dhcpd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: dhcpd.service
enabled: false
mask: true
- name: dhcpd.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_dhcpd
class disable_dhcpd {
service {'dhcpd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["dhcpd"]
|
DNS Server
[ref]groupMost organizations have an operational need to run at
least one nameserver. However, there are many common attacks
involving DNS server software, and this server software should
be disabled on any system
on which it is not needed. |
contains 1 rule |
Disable DNS Server
[ref]groupDNS software should be disabled on any systems which does not
need to be a nameserver. Note that the BIND DNS server software is
not installed on Red Hat Enterprise Linux 8 by default. The remainder of this section
discusses secure configuration of systems which must be
nameservers. |
contains 1 rule |
Disable named Service
[ref]rule
The named service can be disabled with the following command:
$ sudo systemctl mask --now named.service Rationale:All network services involve some risk of compromise due to
implementation flaws and should be disabled if possible. Identifiers:
CCE-82409-4 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.11 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service named
block:
- name: Disable service named
systemd:
name: named.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82409-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_named_disabled
- name: Unit Socket Exists - named.socket
command: systemctl list-unit-files named.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82409-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_named_disabled
- name: Disable socket named
systemd:
name: named.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"named.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82409-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_named_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'named.service'
"$SYSTEMCTL_EXEC" disable 'named.service'
"$SYSTEMCTL_EXEC" mask 'named.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^named.socket'; then
"$SYSTEMCTL_EXEC" stop 'named.socket'
"$SYSTEMCTL_EXEC" mask 'named.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'named.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: named.service
enabled: false
mask: true
- name: named.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_named
class disable_named {
service {'named':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["named"]
|
FTP Server
[ref]groupFTP is a common method for allowing remote access to
files. Like telnet, the FTP protocol is unencrypted, which means
that passwords and other data transmitted during the session can be
captured and that the session is vulnerable to hijacking.
Therefore, running the FTP server software is not recommended.
However, there are some FTP server configurations which may
be appropriate for some environments, particularly those which
allow only read-only anonymous access as a means of downloading
data available to the public. |
contains 1 rule |
Disable vsftpd if Possible
[ref]groupTo minimize attack surface, disable vsftpd if at all
possible. |
contains 1 rule |
Disable vsftpd Service
[ref]rule
The vsftpd service can be disabled with the following command:
$ sudo systemctl mask --now vsftpd.service Rationale:Running FTP server software provides a network-based avenue
of attack, and should be disabled if not needed.
Furthermore, the FTP protocol is unencrypted and creates
a risk of compromising sensitive information. Identifiers:
CCE-82413-6 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-001436, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.10 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service vsftpd
block:
- name: Disable service vsftpd
systemd:
name: vsftpd.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82413-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_vsftpd_disabled
- name: Unit Socket Exists - vsftpd.socket
command: systemctl list-unit-files vsftpd.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82413-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_vsftpd_disabled
- name: Disable socket vsftpd
systemd:
name: vsftpd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"vsftpd.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82413-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_vsftpd_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'vsftpd.service'
"$SYSTEMCTL_EXEC" disable 'vsftpd.service'
"$SYSTEMCTL_EXEC" mask 'vsftpd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^vsftpd.socket'; then
"$SYSTEMCTL_EXEC" stop 'vsftpd.socket'
"$SYSTEMCTL_EXEC" mask 'vsftpd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'vsftpd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: vsftpd.service
enabled: false
mask: true
- name: vsftpd.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_vsftpd
class disable_vsftpd {
service {'vsftpd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["vsftpd"]
|
Web Server
[ref]groupThe web server is responsible for providing access to
content via the HTTP protocol. Web servers represent a significant
security risk because:
- The HTTP port is commonly probed by malicious sources
- Web server software is very complex, and includes a long
history of vulnerabilities
- The HTTP protocol is unencrypted and vulnerable to passive
monitoring
The system's default web server software is Apache 2 and is
provided in the RPM package httpd . |
contains 1 rule |
Disable Apache if Possible
[ref]groupIf Apache was installed and activated, but the system
does not need to act as a web server, then it should be disabled
and removed from the system. |
contains 1 rule |
Disable httpd Service
[ref]rule
The httpd service can be disabled with the following command:
$ sudo systemctl mask --now httpd.service Rationale:Running web server software provides a network-based avenue
of attack, and should be disabled if not needed. Identifiers:
CCE-82761-8 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.9 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service httpd
block:
- name: Disable service httpd
systemd:
name: httpd.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82761-8
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_httpd_disabled
- unknown_severity
- name: Unit Socket Exists - httpd.socket
command: systemctl list-unit-files httpd.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82761-8
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_httpd_disabled
- unknown_severity
- name: Disable socket httpd
systemd:
name: httpd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"httpd.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82761-8
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_httpd_disabled
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'httpd.service'
"$SYSTEMCTL_EXEC" disable 'httpd.service'
"$SYSTEMCTL_EXEC" mask 'httpd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^httpd.socket'; then
"$SYSTEMCTL_EXEC" stop 'httpd.socket'
"$SYSTEMCTL_EXEC" mask 'httpd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'httpd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: httpd.service
enabled: false
mask: true
- name: httpd.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_httpd
class disable_httpd {
service {'httpd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["httpd"]
|
IMAP and POP3 Server
[ref]groupDovecot provides IMAP and POP3 services. It is not
installed by default. The project page at
http://www.dovecot.org
contains more detailed information about Dovecot
configuration. |
contains 1 rule |
Disable Dovecot
[ref]groupIf the system does not need to operate as an IMAP or
POP3 server, the dovecot software should be disabled and removed. |
contains 1 rule |
Disable Dovecot Service
[ref]rule
The dovecot service can be disabled with the following command:
$ sudo systemctl mask --now dovecot.service Rationale:Running an IMAP or POP3 server provides a network-based
avenue of attack, and should be disabled if not needed. Identifiers:
CCE-82760-0 References:
2.2.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service dovecot
block:
- name: Disable service dovecot
systemd:
name: dovecot.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82760-0
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_dovecot_disabled
- unknown_severity
- name: Unit Socket Exists - dovecot.socket
command: systemctl list-unit-files dovecot.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82760-0
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_dovecot_disabled
- unknown_severity
- name: Disable socket dovecot
systemd:
name: dovecot.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"dovecot.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82760-0
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_dovecot_disabled
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'dovecot.service'
"$SYSTEMCTL_EXEC" disable 'dovecot.service'
"$SYSTEMCTL_EXEC" mask 'dovecot.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^dovecot.socket'; then
"$SYSTEMCTL_EXEC" stop 'dovecot.socket'
"$SYSTEMCTL_EXEC" mask 'dovecot.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'dovecot.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: dovecot.service
enabled: false
mask: true
- name: dovecot.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_dovecot
class disable_dovecot {
service {'dovecot':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["dovecot"]
|
LDAP is a popular directory service, that is, a
standardized way of looking up information from a central database.
Red Hat Enterprise Linux 8 includes software that enables a system to act as both
an LDAP client and server. |
contains 2 rules |
Configure OpenLDAP Clients
[ref]groupThis section provides information on which security settings are
important to configure in OpenLDAP clients by manually editing the appropriate
configuration files. Red Hat Enterprise Linux 8 provides an automated configuration tool called
authconfig and a graphical wrapper for authconfig called
system-config-authentication . However, these tools do not provide as
much control over configuration as manual editing of configuration files. The
authconfig tools do not allow you to specify locations of SSL certificate
files, which is useful when trying to use SSL cleanly across several protocols.
Installation and configuration of OpenLDAP on Red Hat Enterprise Linux 8 is available at Warning:
Before configuring any system to be an
LDAP client, ensure that a working LDAP server is present on the
network. |
contains 1 rule |
Ensure LDAP client is not installed
[ref]ruleThe Lightweight Directory Access Protocol (LDAP) is a service that provides
a method for looking up information from a central database.
The openldap-clients package can be removed with the following command:
$ sudo yum erase openldap-clients Rationale:If the system does not need to act as an LDAP client, it is recommended that the software is removed to reduce the potential attack surface. Identifiers:
CCE-82885-5 References:
2.3.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure openldap-clients is removed
package:
name: openldap-clients
state: absent
tags:
- CCE-82885-5
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_openldap-clients_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove openldap-clients
# from the system, and may remove any packages
# that depend on openldap-clients. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "openldap-clients" ; then
yum remove -y "openldap-clients"
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=openldap-clients
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_openldap-clients
class remove_openldap-clients {
package { 'openldap-clients':
ensure => 'purged',
}
}
|
Configure OpenLDAP Server
[ref]groupThis section details some security-relevant settings
for an OpenLDAP server. |
contains 1 rule |
Disable LDAP Server (slapd)
[ref]ruleThe Lightweight Directory Access Protocol (LDAP) is a service that provides a method for looking up information from a central database. Rationale:If the system will not need to act as an LDAP server, it is recommended that the software be
disabled to reduce the potential attack surface. Identifiers:
CCE-87262-2 References:
2.2.14 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service slapd
block:
- name: Disable service slapd
systemd:
name: slapd.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-87262-2
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_slapd_disabled
- name: Unit Socket Exists - slapd.socket
command: systemctl list-unit-files slapd.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-87262-2
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_slapd_disabled
- name: Disable socket slapd
systemd:
name: slapd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"slapd.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-87262-2
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_slapd_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'slapd.service'
"$SYSTEMCTL_EXEC" disable 'slapd.service'
"$SYSTEMCTL_EXEC" mask 'slapd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^slapd.socket'; then
"$SYSTEMCTL_EXEC" stop 'slapd.socket'
"$SYSTEMCTL_EXEC" mask 'slapd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'slapd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: slapd.service
enabled: false
mask: true
- name: slapd.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_slapd
class disable_slapd {
service {'slapd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["slapd"]
|
Mail Server Software
[ref]groupMail servers are used to send and receive email over the network.
Mail is a very common service, and Mail Transfer Agents (MTAs) are obvious
targets of network attack.
Ensure that systems are not running MTAs unnecessarily,
and configure needed MTAs as defensively as possible.
Very few systems at any site should be configured to directly receive email over the
network. Users should instead use mail client programs to retrieve email
from a central server that supports protocols such as IMAP or POP3.
However, it is normal for most systems to be independently capable of sending email,
for instance so that cron jobs can report output to an administrator.
Most MTAs, including Postfix, support a submission-only mode in which mail can be sent from
the local system to a central site MTA (or directly delivered to a local account),
but the system still cannot receive mail directly over a network.
The alternatives program in Red Hat Enterprise Linux 8 permits selection of other mail server software
(such as Sendmail), but Postfix is the default and is preferred.
Postfix was coded with security in mind and can also be more effectively contained by
SELinux as its modular design has resulted in separate processes performing specific actions.
More information is available on its website,
http://www.postfix.org. |
contains 1 rule |
Configure SMTP For Mail Clients
[ref]groupThis section discusses settings for Postfix in a submission-only
e-mail configuration. |
contains 1 rule |
Disable Postfix Network Listening
[ref]ruleEdit the file /etc/postfix/main.cf to ensure that only the following
inet_interfaces line appears:
inet_interfaces = loopback-only Rationale:This ensures postfix accepts mail messages
(such as cron job reports) from the local system only,
and not from the network, which protects it from network attack. Identifiers:
CCE-82174-4 References:
BP28(R48), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000382, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.18 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_postfix_inet_interfaces # promote to variable
set_fact:
var_postfix_inet_interfaces: !!str loopback-only
tags:
- always
- name: Gather list of packages
package_facts:
manager: auto
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82174-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- postfix_network_listening_disabled
- restrict_strategy
- name: Make changes to Postfix configuration file
lineinfile:
path: /etc/postfix/main.cf
create: false
regexp: ^inet_interfaces\s*=\s.*
line: inet_interfaces = {{ var_postfix_inet_interfaces }}
state: present
insertafter: ^inet_interfaces\s*=\s.*
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"postfix" in ansible_facts.packages'
- '"postfix" in ansible_facts.packages'
tags:
- CCE-82174-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- postfix_network_listening_disabled
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q postfix; }; then
var_postfix_inet_interfaces='loopback-only'
if [ -e "/etc/postfix/main.cf" ] ; then
LC_ALL=C sed -i "/^\s*inet_interfaces\s\+=\s\+/Id" "/etc/postfix/main.cf"
else
touch "/etc/postfix/main.cf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/postfix/main.cf"
cp "/etc/postfix/main.cf" "/etc/postfix/main.cf.bak"
# Insert at the end of the file
printf '%s\n' "inet_interfaces=$var_postfix_inet_interfaces" >> "/etc/postfix/main.cf"
# Clean up after ourselves.
rm "/etc/postfix/main.cf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
NFS and RPC
[ref]groupThe Network File System is a popular distributed filesystem for
the Unix environment, and is very widely deployed. This section discusses the
circumstances under which it is possible to disable NFS and its dependencies,
and then details steps which should be taken to secure
NFS's configuration. This section is relevant to systems operating as NFS
clients, as well as to those operating as NFS servers. |
contains 2 rules |
Disable All NFS Services if Possible
[ref]groupIf there is not a reason for the system to operate as either an
NFS client or an NFS server, follow all instructions in this section to disable
subsystems required by NFS. Warning:
The steps in this section will prevent a system
from operating as either an NFS client or an NFS server. Only perform these
steps on systems which do not need NFS at all. |
contains 1 rule |
Disable Services Used Only by NFS
[ref]groupIf NFS is not needed, disable the NFS client daemons nfslock, rpcgssd, and rpcidmapd.
All of these daemons run with elevated privileges, and many listen for network
connections. If they are not needed, they should be disabled to improve system
security posture. |
contains 1 rule |
Disable rpcbind Service
[ref]ruleThe rpcbind utility maps RPC services to the ports on which they listen.
RPC processes notify rpcbind when they start, registering the ports they
are listening on and the RPC program numbers they expect to serve. The
rpcbind service redirects the client to the proper port number so it can
communicate with the requested service. If the system does not require RPC
(such as for NFS servers) then this service should be disabled.
The rpcbind service can be disabled with the following command:
$ sudo systemctl mask --now rpcbind.service Rationale:If the system does not require rpc based services, it is recommended that
rpcbind be disabled to reduce the attack surface. Identifiers:
CCE-82858-2 References:
2.2.13 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service rpcbind
block:
- name: Disable service rpcbind
systemd:
name: rpcbind.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82858-2
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_rpcbind_disabled
- name: Unit Socket Exists - rpcbind.socket
command: systemctl list-unit-files rpcbind.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82858-2
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_rpcbind_disabled
- name: Disable socket rpcbind
systemd:
name: rpcbind.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"rpcbind.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82858-2
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_rpcbind_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'rpcbind.service'
"$SYSTEMCTL_EXEC" disable 'rpcbind.service'
"$SYSTEMCTL_EXEC" mask 'rpcbind.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^rpcbind.socket'; then
"$SYSTEMCTL_EXEC" stop 'rpcbind.socket'
"$SYSTEMCTL_EXEC" mask 'rpcbind.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'rpcbind.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: rpcbind.service
enabled: false
mask: true
- name: rpcbind.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_rpcbind
class disable_rpcbind {
service {'rpcbind':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["rpcbind"]
|
Configure NFS Clients
[ref]groupThe steps in this section are appropriate for systems which operate as NFS clients. |
contains 1 rule |
Disable NFS Server Daemons
[ref]groupThere is no need to run the NFS server daemons nfs and
rpcsvcgssd except on a small number of properly secured systems
designated as NFS servers. Ensure that these daemons are turned off on
clients. |
contains 1 rule |
Disable Network File System (nfs)
[ref]ruleThe Network File System (NFS) service allows remote hosts to mount
and interact with shared filesystems on the local system. If the local system
is not designated as a NFS server then this service should be disabled.
The nfs-server service can be disabled with the following command:
$ sudo systemctl mask --now nfs-server.service Rationale:Unnecessary services should be disabled to decrease the attack surface of the system. Identifiers:
CCE-82762-6 References:
11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, 2.2.12 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service nfs-server
block:
- name: Disable service nfs-server
systemd:
name: nfs-server.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82762-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_nfs_disabled
- unknown_severity
- name: Unit Socket Exists - nfs-server.socket
command: systemctl list-unit-files nfs-server.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82762-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_nfs_disabled
- unknown_severity
- name: Disable socket nfs-server
systemd:
name: nfs-server.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"nfs-server.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82762-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_nfs_disabled
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'nfs-server.service'
"$SYSTEMCTL_EXEC" disable 'nfs-server.service'
"$SYSTEMCTL_EXEC" mask 'nfs-server.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^nfs-server.socket'; then
"$SYSTEMCTL_EXEC" stop 'nfs-server.socket'
"$SYSTEMCTL_EXEC" mask 'nfs-server.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'nfs-server.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: nfs-server.service
enabled: false
mask: true
- name: nfs-server.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_nfs-server
class disable_nfs-server {
service {'nfs-server':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["nfs-server"]
|
Network Time Protocol
[ref]groupThe Network Time Protocol is used to manage the system
clock over a network. Computer clocks are not very accurate, so
time will drift unpredictably on unmanaged systems. Central time
protocols can be used both to ensure that time is consistent among
a network of systems, and that their time is consistent with the
outside world.
If every system on a network reliably reports the same time, then it is much
easier to correlate log messages in case of an attack. In addition, a number of
cryptographic protocols (such as Kerberos) use timestamps to prevent certain
types of attacks. If your network does not have synchronized time, these
protocols may be unreliable or even unusable.
Depending on the specifics of the network, global time accuracy may be just as
important as local synchronization, or not very important at all. If your
network is connected to the Internet, using a public timeserver (or one
provided by your enterprise) provides globally accurate timestamps which may be
essential in investigating or responding to an attack which originated outside
of your network.
A typical network setup involves a small number of internal systems operating
as NTP servers, and the remainder obtaining time information from those
internal servers.
There is a choice between the daemons ntpd and chronyd , which
are available from the repositories in the ntp and chrony
packages respectively.
The default chronyd daemon can work well when external time references
are only intermittently accesible, can perform well even when the network is
congested for longer periods of time, can usually synchronize the clock faster
and with better time accuracy, and quickly adapts to sudden changes in the rate
of the clock, for example, due to changes in the temperature of the crystal
oscillator. Chronyd should be considered for all systems which are
frequently suspended or otherwise intermittently disconnected and reconnected
to a network. Mobile and virtual systems for example.
The ntpd NTP daemon fully supports NTP protocol version 4 (RFC 5905),
including broadcast, multicast, manycast clients and servers, and the orphan
mode. It also supports extra authentication schemes based on public-key
cryptography (RFC 5906). The NTP daemon (ntpd ) should be considered
for systems which are normally kept permanently on. Systems which are required
to use broadcast or multicast IP, or to perform authentication of packets with
the Autokey protocol, should consider using ntpd .
Refer to
https://docs.fedoraproject.org/en-US/fedora/rawhide/system-administrators-guide/servers/Configuring_NTP_Using_the_chrony_Suite/
for more detailed comparison of features of chronyd
and ntpd daemon features respectively, and for further guidance how to
choose between the two NTP daemons.
The upstream manual pages at
http://chrony.tuxfamily.org/manual.html for
chronyd and
http://www.ntp.org for ntpd provide additional
information on the capabilities and configuration of each of the NTP daemons. |
contains 2 rules |
Ensure that chronyd is running under chrony user account
[ref]rulechrony is a daemon which implements the Network Time Protocol (NTP). It is designed to
synchronize system clocks across a variety of systems and use a source that is highly
accurate. More information on chrony can be found at
http://chrony.tuxfamily.org/.
Chrony can be configured to be a client and/or a server.
To ensure that chronyd is running under chrony user account, Add or edit the
OPTIONS variable in /etc/sysconfig/chronyd to include -u chrony :
OPTIONS="-u chrony"
This recommendation only applies if chrony is in use on the system.Rationale:If chrony is in use on the system proper configuration is vital to ensuring time synchronization
is working properly. Identifiers:
CCE-82879-8 References:
2.2.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-82879-8
- chronyd_run_as_chrony_user
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Detect if file /etc/sysconfig/chronyd is not empty or missing
find:
path: /etc/sysconfig/
patterns: chronyd
contains: ^([\s]*OPTIONS=["]?[^"]*)("?)
register: chronyd_file
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
tags:
- CCE-82879-8
- chronyd_run_as_chrony_user
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Remove any previous configuration of user used to run chronyd process
replace:
path: /etc/sysconfig/chronyd
regexp: \s*-u\s+\w+\s*
replace: ' '
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
- chronyd_file is defined and chronyd_file.matched > 0
tags:
- CCE-82879-8
- chronyd_run_as_chrony_user
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Correct existing line in /etc/sysconfig/chronyd to run chronyd as chrony user
lineinfile:
path: /etc/sysconfig/chronyd
regexp: ^([\s]*OPTIONS=["]?[^"]*)("?)
line: \1 -u chrony\2
state: present
backrefs: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
- chronyd_file is defined and chronyd_file.matched > 0
tags:
- CCE-82879-8
- chronyd_run_as_chrony_user
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Insert correct line into /etc/sysconfig/chronyd ensuring chronyd runs as chrony
user
lineinfile:
path: /etc/sysconfig/chronyd
line: OPTIONS="-u chrony"
state: present
create: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
- chronyd_file is defined and chronyd_file.matched == 0
tags:
- CCE-82879-8
- chronyd_run_as_chrony_user
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q chrony; }; then
if grep -q 'OPTIONS=.*' /etc/sysconfig/chronyd; then
# trying to solve cases where the parameter after OPTIONS
#may or may not be enclosed in quotes
sed -i -E -e 's/\s*-u\s+\w+\s*/ /' -e 's/^([\s]*OPTIONS=["]?[^"]*)("?)/\1 -u chrony\2/' /etc/sysconfig/chronyd
else
echo 'OPTIONS="-u chrony"' >> /etc/sysconfig/chronyd
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
A remote time server for Chrony is configured
[ref]ruleChrony is a daemon which implements the Network Time Protocol (NTP). It is designed to
synchronize system clocks across a variety of systems and use a source that is highly
accurate. More information on chrony can be found at
http://chrony.tuxfamily.org/.
Chrony can be configured to be a client and/or a server.
Add or edit server or pool lines to /etc/chrony.conf as appropriate:
server <remote-server>
Multiple servers may be configured.Rationale:If chrony is in use on the system proper configuration is vital to ensuring time
synchronization is working properly. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-82873-1
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_multiple_time_servers # promote to variable
set_fact:
var_multiple_time_servers: !!str 0.rhel.pool.ntp.org,1.rhel.pool.ntp.org,2.rhel.pool.ntp.org,3.rhel.pool.ntp.org
tags:
- always
- name: Detect if chrony is already configured with pools or servers
find:
path: /etc
patterns: chrony.conf
contains: ^[\s]*(?:server|pool)[\s]+[\w]+
register: chrony_servers
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
tags:
- CCE-82873-1
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure remote time servers
lineinfile:
path: /etc/chrony.conf
line: server {{ item }}
state: present
create: true
loop: '{{ var_multiple_time_servers.split(",") }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
- chrony_servers.matched == 0
tags:
- CCE-82873-1
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q chrony; }; then
var_multiple_time_servers='0.rhel.pool.ntp.org,1.rhel.pool.ntp.org,2.rhel.pool.ntp.org,3.rhel.pool.ntp.org'
config_file="/etc/chrony.conf"
if ! grep -q '^[\s]*(?:server|pool)[\s]+[\w]+' "$config_file" ; then
if ! grep -q '#[[:space:]]*server' "$config_file" ; then
for server in $(echo "$var_multiple_time_servers" | tr ',' '\n') ; do
printf '\nserver %s' "$server" >> "$config_file"
done
else
sed -i 's/#[ \t]*server/server/g' "$config_file"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Obsolete Services
[ref]groupThis section discusses a number of network-visible
services which have historically caused problems for system
security, and for which disabling or severely limiting the service
has been the best available guidance for some time. As a result of
this, many of these services are not installed as part of Red Hat Enterprise Linux 8
by default.
Organizations which are running these services should
switch to more secure equivalents as soon as possible.
If it remains absolutely necessary to run one of
these services for legacy reasons, care should be taken to restrict
the service as much as possible, for instance by configuring host
firewall software such as iptables to restrict access to the
vulnerable service to only those remote hosts which have a known
need to use it. |
contains 6 rules |
Xinetd
[ref]groupThe xinetd service acts as a dedicated listener for some
network services (mostly, obsolete ones) and can be used to provide access
controls and perform some logging. It has been largely obsoleted by other
features, and it is not installed by default. The older Inetd service
is not even available as part of Red Hat Enterprise Linux 8. |
contains 1 rule |
Uninstall xinetd Package
[ref]ruleThe xinetd package can be removed with the following command:
$ sudo yum erase xinetd Rationale:Removing the xinetd package decreases the risk of the
xinetd service's accidental (or intentional) activation. Identifiers:
CCE-80850-1 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, 2.1.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure xinetd is removed
package:
name: xinetd
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80850-1
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_xinetd_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# CAUTION: This remediation script will remove xinetd
# from the system, and may remove any packages
# that depend on xinetd. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "xinetd" ; then
yum remove -y "xinetd"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=xinetd
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_xinetd
class remove_xinetd {
package { 'xinetd':
ensure => 'purged',
}
}
|
The Network Information Service (NIS), also known as 'Yellow
Pages' (YP), and its successor NIS+ have been made obsolete by
Kerberos, LDAP, and other modern centralized authentication
services. NIS should not be used because it suffers from security
problems inherent in its design, such as inadequate protection of
important authentication information. |
contains 2 rules |
Remove NIS Client
[ref]ruleThe Network Information Service (NIS), formerly known as Yellow Pages,
is a client-server directory service protocol used to distribute system configuration
files. The NIS client (ypbind ) was used to bind a system to an NIS server
and receive the distributed configuration files. Rationale:The NIS service is inherently an insecure system that has been vulnerable
to DOS attacks, buffer overflows and has poor authentication for querying
NIS maps. NIS generally has been replaced by such protocols as Lightweight
Directory Access Protocol (LDAP). It is recommended that the service be
removed. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure ypbind is removed
package:
name: ypbind
state: absent
tags:
- CCE-82181-9
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_ypbind_removed
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove ypbind
# from the system, and may remove any packages
# that depend on ypbind. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "ypbind" ; then
yum remove -y "ypbind"
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=ypbind
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_ypbind
class remove_ypbind {
package { 'ypbind':
ensure => 'purged',
}
}
|
Disable ypserv Service
[ref]ruleThe ypserv service, which allows the system to act as a client in
a NIS or NIS+ domain, should be disabled.
The ypserv service can be disabled with the following command:
$ sudo systemctl mask --now ypserv.service Rationale:Disabling the ypserv service ensures the system is not acting
as a client in a NIS or NIS+ domain. This service should be disabled
unless in use. Identifiers:
CCE-86121-1 References:
2.2.17 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service ypserv
block:
- name: Disable service ypserv
systemd:
name: ypserv.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86121-1
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_ypserv_disabled
- name: Unit Socket Exists - ypserv.socket
command: systemctl list-unit-files ypserv.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86121-1
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_ypserv_disabled
- name: Disable socket ypserv
systemd:
name: ypserv.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"ypserv.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-86121-1
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_ypserv_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'ypserv.service'
"$SYSTEMCTL_EXEC" disable 'ypserv.service'
"$SYSTEMCTL_EXEC" mask 'ypserv.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^ypserv.socket'; then
"$SYSTEMCTL_EXEC" stop 'ypserv.socket'
"$SYSTEMCTL_EXEC" mask 'ypserv.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'ypserv.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: ypserv.service
enabled: false
mask: true
- name: ypserv.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_ypserv
class disable_ypserv {
service {'ypserv':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["ypserv"]
|
Rlogin, Rsh, and Rexec
[ref]groupThe Berkeley r-commands are legacy services which
allow cleartext remote access and have an insecure trust
model. |
contains 1 rule |
Remove Rsh Trust Files
[ref]ruleThe files /etc/hosts.equiv and ~/.rhosts (in
each user's home directory) list remote hosts and users that are trusted by the
local system when using the rshd daemon.
To remove these files, run the following command to delete them from any
location:
$ sudo rm /etc/hosts.equiv
$ rm ~/.rhosts Rationale:This action is only meaningful if .rhosts support is permitted
through PAM. Trust files are convenient, but when used in conjunction with
the R-services, they can allow unauthenticated access to a system. Identifiers:
CCE-80842-8 References:
11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, 6.2.13 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- block:
- name: Detect .rhosts files in users home directories
find:
paths:
- /root
- /home
recurse: true
patterns: .rhosts
hidden: true
file_type: file
check_mode: false
register: rhosts_locations
- name: Remove .rhosts files
file:
path: '{{ item }}'
state: absent
with_items: '{{ rhosts_locations.files | map(attribute=''path'') | list }}'
when: rhosts_locations is success
- name: Remove /etc/hosts.equiv file
file:
path: /etc/hosts.equiv
state: absent
tags:
- CCE-80842-8
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- no_rsh_trust_files
- restrict_strategy
Remediation Shell script: (show)
find /root -xdev -type f -name ".rhosts" -exec rm -f {} \;
find /home -maxdepth 2 -xdev -type f -name ".rhosts" -exec rm -f {} \;
rm -f /etc/hosts.equiv
|
Telnet
[ref]groupThe telnet protocol does not provide confidentiality or integrity
for information transmitted on the network. This includes authentication
information such as passwords. Organizations which use telnet should be
actively working to migrate to a more secure protocol. |
contains 1 rule |
Remove telnet Clients
[ref]ruleThe telnet client allows users to start connections to other systems via
the telnet protocol. Rationale:The telnet protocol is insecure and unencrypted. The use
of an unencrypted transmission medium could allow an unauthorized user
to steal credentials. The ssh package provides an
encrypted session and stronger security and is included in Red Hat Enterprise Linux 8. Identifiers:
CCE-80849-3 References:
BP28(R1), 3.1.13, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3, 2.3.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure telnet is removed
package:
name: telnet
state: absent
tags:
- CCE-80849-3
- NIST-800-171-3.1.13
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_telnet_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove telnet
# from the system, and may remove any packages
# that depend on telnet. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "telnet" ; then
yum remove -y "telnet"
fi
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=telnet
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_telnet
class remove_telnet {
package { 'telnet':
ensure => 'purged',
}
}
|
Ensure rsyncd service is diabled
[ref]rule
The rsyncd service can be disabled with the following command:
$ sudo systemctl mask --now rsyncd.service Rationale:The rsyncd service presents a security risk as it uses unencrypted protocols for
communication. Identifiers:
CCE-83335-0 References:
2.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service rsyncd
block:
- name: Disable service rsyncd
systemd:
name: rsyncd.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83335-0
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_rsyncd_disabled
- name: Unit Socket Exists - rsyncd.socket
command: systemctl list-unit-files rsyncd.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83335-0
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_rsyncd_disabled
- name: Disable socket rsyncd
systemd:
name: rsyncd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"rsyncd.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-83335-0
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_rsyncd_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'rsyncd.service'
"$SYSTEMCTL_EXEC" disable 'rsyncd.service'
"$SYSTEMCTL_EXEC" mask 'rsyncd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^rsyncd.socket'; then
"$SYSTEMCTL_EXEC" stop 'rsyncd.socket'
"$SYSTEMCTL_EXEC" mask 'rsyncd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'rsyncd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: rsyncd.service
enabled: false
mask: true
- name: rsyncd.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_rsyncd
class disable_rsyncd {
service {'rsyncd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["rsyncd"]
|
Print Support
[ref]groupThe Common Unix Printing System (CUPS) service provides both local
and network printing support. A system running the CUPS service can accept
print jobs from other systems, process them, and send them to the appropriate
printer. It also provides an interface for remote administration through a web
browser. The CUPS service is installed and activated by default. The project
homepage and more detailed documentation are available at
http://www.cups.org.
|
contains 1 rule |
Disable the CUPS Service
[ref]rule
The cups service can be disabled with the following command:
$ sudo systemctl mask --now cups.service Rationale:Turn off unneeded services to reduce attack surface. Identifiers:
CCE-82861-6 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.16 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service cups
block:
- name: Disable service cups
systemd:
name: cups.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82861-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_cups_disabled
- unknown_severity
- name: Unit Socket Exists - cups.socket
command: systemctl list-unit-files cups.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82861-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_cups_disabled
- unknown_severity
- name: Disable socket cups
systemd:
name: cups.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"cups.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82861-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_cups_disabled
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'cups.service'
"$SYSTEMCTL_EXEC" disable 'cups.service'
"$SYSTEMCTL_EXEC" mask 'cups.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^cups.socket'; then
"$SYSTEMCTL_EXEC" stop 'cups.socket'
"$SYSTEMCTL_EXEC" mask 'cups.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'cups.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: cups.service
enabled: false
mask: true
- name: cups.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_cups
class disable_cups {
service {'cups':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["cups"]
|
Proxy Server
[ref]groupA proxy server is a very desirable target for a
potential adversary because much (or all) sensitive data for a
given infrastructure may flow through it. Therefore, if one is
required, the system acting as a proxy server should be dedicated
to that purpose alone and be stored in a physically secure
location. The system's default proxy server software is Squid, and
provided in an RPM package of the same name. |
contains 1 rule |
Disable Squid if Possible
[ref]groupIf Squid was installed and activated, but the system
does not need to act as a proxy server, then it should be disabled
and removed. |
contains 1 rule |
Disable Squid
[ref]rule
The squid service can be disabled with the following command:
$ sudo systemctl mask --now squid.service Rationale:Running proxy server software provides a network-based avenue
of attack, and should be removed if not needed. Identifiers:
CCE-82190-0 References:
2.2.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service squid
block:
- name: Disable service squid
systemd:
name: squid.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82190-0
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_squid_disabled
- unknown_severity
- name: Unit Socket Exists - squid.socket
command: systemctl list-unit-files squid.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82190-0
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_squid_disabled
- unknown_severity
- name: Disable socket squid
systemd:
name: squid.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"squid.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82190-0
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_squid_disabled
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'squid.service'
"$SYSTEMCTL_EXEC" disable 'squid.service'
"$SYSTEMCTL_EXEC" mask 'squid.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^squid.socket'; then
"$SYSTEMCTL_EXEC" stop 'squid.socket'
"$SYSTEMCTL_EXEC" mask 'squid.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'squid.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: squid.service
enabled: false
mask: true
- name: squid.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_squid
class disable_squid {
service {'squid':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["squid"]
|
Samba(SMB) Microsoft Windows File Sharing Server
[ref]groupWhen properly configured, the Samba service allows
Linux systems to provide file and print sharing to Microsoft
Windows systems. There are two software packages that provide
Samba support. The first, samba-client , provides a series of
command line tools that enable a client system to access Samba
shares. The second, simply labeled samba , provides the Samba
service. It is this second package that allows a Linux system to
act as an Active Directory server, a domain controller, or as a
domain member. Only the samba-client package is installed by
default. |
contains 1 rule |
Disable Samba if Possible
[ref]groupEven after the Samba server package has been installed, it
will remain disabled. Do not enable this service unless it is
absolutely necessary to provide Microsoft Windows file and print
sharing functionality. |
contains 1 rule |
Disable Samba
[ref]rule
The smb service can be disabled with the following command:
$ sudo systemctl mask --now smb.service Rationale:Running a Samba server provides a network-based avenue of attack, and
should be disabled if not needed. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service smb
block:
- name: Disable service smb
systemd:
name: smb.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82759-2
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_smb_disabled
- name: Unit Socket Exists - smb.socket
command: systemctl list-unit-files smb.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82759-2
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_smb_disabled
- name: Disable socket smb
systemd:
name: smb.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"smb.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82759-2
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_smb_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'smb.service'
"$SYSTEMCTL_EXEC" disable 'smb.service'
"$SYSTEMCTL_EXEC" mask 'smb.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^smb.socket'; then
"$SYSTEMCTL_EXEC" stop 'smb.socket'
"$SYSTEMCTL_EXEC" mask 'smb.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'smb.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: smb.service
enabled: false
mask: true
- name: smb.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_smb
class disable_smb {
service {'smb':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["smb"]
|
SNMP Server
[ref]groupThe Simple Network Management Protocol allows
administrators to monitor the state of network devices, including
computers. Older versions of SNMP were well-known for weak
security, such as plaintext transmission of the community string
(used for authentication) and usage of easily-guessable
choices for the community string. |
contains 1 rule |
Disable SNMP Server if Possible
[ref]groupThe system includes an SNMP daemon that allows for its remote
monitoring, though it not installed by default. If it was installed and
activated but is not needed, the software should be disabled and removed. |
contains 1 rule |
Disable snmpd Service
[ref]rule
The snmpd service can be disabled with the following command:
$ sudo systemctl mask --now snmpd.service Rationale:Running SNMP software provides a network-based avenue of attack, and
should be disabled if not needed. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Disable service snmpd
block:
- name: Disable service snmpd
systemd:
name: snmpd.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82758-4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_snmpd_disabled
- name: Unit Socket Exists - snmpd.socket
command: systemctl list-unit-files snmpd.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82758-4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_snmpd_disabled
- name: Disable socket snmpd
systemd:
name: snmpd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"snmpd.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-82758-4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_snmpd_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'snmpd.service'
"$SYSTEMCTL_EXEC" disable 'snmpd.service'
"$SYSTEMCTL_EXEC" mask 'snmpd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^snmpd.socket'; then
"$SYSTEMCTL_EXEC" stop 'snmpd.socket'
"$SYSTEMCTL_EXEC" mask 'snmpd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'snmpd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: snmpd.service
enabled: false
mask: true
- name: snmpd.socket
enabled: false
mask: true
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_snmpd
class disable_snmpd {
service {'snmpd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["snmpd"]
|
SSH Server
[ref]groupThe SSH protocol is recommended for remote login and
remote file transfer. SSH provides confidentiality and integrity
for data exchanged between two systems, as well as server
authentication, through the use of public key cryptography. The
implementation included with the system is called OpenSSH, and more
detailed documentation is available from its website,
https://www.openssh.com.
Its server program is called sshd and provided by the RPM package
openssh-server . |
contains 19 rules |
Configure OpenSSH Server if Necessary
[ref]groupIf the system needs to act as an SSH server, then
certain changes should be made to the OpenSSH daemon configuration
file /etc/ssh/sshd_config . The following recommendations can be
applied to this file. See the sshd_config(5) man page for more
detailed information. |
contains 15 rules |
Set SSH Client Alive Count Max
[ref]ruleThe SSH server sends at most ClientAliveCountMax messages
during a SSH session and waits for a response from the SSH client.
The option ClientAliveInterval configures timeout after
each ClientAliveCountMax message. If the SSH server does not
receive a response from the client, then the connection is considered idle
and terminated.
For SSH earlier than v8.2, a ClientAliveCountMax value of 0
causes an idle timeout precisely when the ClientAliveInterval is set.
Starting with v8.2, a value of 0 disables the timeout functionality
completely. If the option is set to a number greater than 0 , then
the idle session will be disconnected after
ClientAliveInterval * ClientAliveCountMax seconds. Rationale:This ensures a user login will be terminated as soon as the ClientAliveInterval
is reached. Identifiers:
CCE-80907-9 References:
BP28(R29), 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000480-VMM-002000, 5.2.13 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sshd_set_keepalive # promote to variable
set_fact:
var_sshd_set_keepalive: !!str 0
tags:
- always
- name: Set SSH Client Alive Count Max
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveCountMax\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveCountMax\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveCountMax\s+
line: ClientAliveCountMax {{ var_sshd_set_keepalive }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80907-9
- CJIS-5.5.6
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSS-Req-8.1.8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_keepalive
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_set_keepalive='0'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*ClientAliveCountMax\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "ClientAliveCountMax $var_sshd_set_keepalive" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "ClientAliveCountMax $var_sshd_set_keepalive" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set SSH Idle Timeout Interval
[ref]ruleSSH allows administrators to set an idle timeout interval. After this interval
has passed, the idle user will be automatically logged out.
To set an idle timeout interval, edit the following line in /etc/ssh/sshd_config as
follows:
ClientAliveInterval 900
The timeout interval is given in seconds. For example, have a timeout
of 10 minutes, set interval to 600.
If a shorter timeout has already been set for the login shell, that value will
preempt any SSH setting made in /etc/ssh/sshd_config . Keep in mind that
some processes may stop SSH from correctly detecting that the user is idle.Warning:
SSH disconnecting idle clients will not have desired effect without also
configuring ClientAliveCountMax in the SSH service configuration. Warning:
Following conditions may prevent the SSH session to time out:
- Remote processes on the remote machine generates output. As the output has to be transferred over the network to the client, the timeout is reset every time such transfer happens.
- Any
scp or sftp activity by the same user to the host resets the timeout.
Rationale:Terminating an idle ssh session within a short time period reduces the window of
opportunity for unauthorized personnel to take control of a management session
enabled on the console or console port that has been let unattended. Identifiers:
CCE-80906-1 References:
BP28(R29), 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CM-6(a), AC-17(a), AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000395-GPOS-00175, SRG-OS-000480-VMM-002000, RHEL-08-010201, 5.2.13, SV-244525r743824_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_idle_timeout_value # promote to variable
set_fact:
sshd_idle_timeout_value: !!str 900
tags:
- always
- name: Set SSH Idle Timeout Interval
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveInterval\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveInterval\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveInterval\s+
line: ClientAliveInterval {{ sshd_idle_timeout_value }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80906-1
- CJIS-5.5.6
- DISA-STIG-RHEL-08-010201
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSS-Req-8.1.8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_idle_timeout
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_idle_timeout_value='900'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*ClientAliveInterval\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "ClientAliveInterval $sshd_idle_timeout_value" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "ClientAliveInterval $sshd_idle_timeout_value" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Host-Based Authentication
[ref]ruleSSH's cryptographic host-based authentication is
more secure than .rhosts authentication. However, it is
not recommended that hosts unilaterally trust one another, even
within an organization.
The default SSH configuration disables host-based authentication. The appropriate
configuration is used if no value is set for HostbasedAuthentication .
To explicitly disable host-based authentication, add or correct the
following line in
/etc/ssh/sshd_config :
HostbasedAuthentication no Rationale:SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts. Identifiers:
CCE-80786-7 References:
11, 12, 14, 15, 16, 18, 3, 5, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-3, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3, FIA_UAU.1, SRG-OS-000480-GPOS-00229, SRG-OS-000480-VMM-002000, 5.2.9 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable Host-Based Authentication
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*HostbasedAuthentication\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*HostbasedAuthentication\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*HostbasedAuthentication\s+
line: HostbasedAuthentication no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80786-7
- CJIS-5.5.6
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-3
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_host_auth
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*HostbasedAuthentication\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "HostbasedAuthentication no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "HostbasedAuthentication no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018%2F04%2F09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D%2Fusr%2Flocal%2Fbin%3A%2Fusr%2Fbin%3A%2Fusr%2Flocal%2Fsbin%3A%2Fusr%2Fsbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20%2Fetc%2Fssh%2Fssh_host_rsa_key%0AHostKey%20%2Fetc%2Fssh%2Fssh_host_ecdsa_key%0AHostKey%20%2Fetc%2Fssh%2Fssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20%2Fetc%2Fsysconfig%2Fsshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh%2Fauthorized_keys%20and%20.ssh%2Fauthorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh%2Fauthorized_keys%0AAuthorizedKeysFile%09.ssh%2Fauthorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20%2Fetc%2Fssh%2Fssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~%2F.ssh%2Fknown_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~%2F.rhosts%20and%20~%2F.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s%2Fkey%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20%2Fetc%2Fpam.d%2Fsshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20%2Fvar%2Frun%2Fsshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20%2Fetc%2Fissue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09%2Fusr%2Flibexec%2Fopenssh%2Fsftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
mode: 0600
path: /etc/ssh/sshd_config
overwrite: true
|
Disable SSH Access via Empty Passwords
[ref]ruleDisallow SSH login with empty passwords.
The default SSH configuration disables logins with empty passwords. The appropriate
configuration is used if no value is set for PermitEmptyPasswords .
To explicitly disallow SSH login from accounts with empty passwords,
add or correct the following line in
/etc/ssh/sshd_config :
PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration
should prevent users from being able to assign themselves empty passwords.Rationale:Configuring this setting for the SSH daemon provides additional assurance
that remote login via SSH will require a password, even in the event of
misconfiguration elsewhere. Identifiers:
CCE-80896-4 References:
NT007(R17), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, 5.5.6, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, 3.1.1, 3.1.5, CCI-000366, CCI-000766, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, FIA_UAU.1, SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000, RHEL-08-020330, 5.2.11, SV-230380r743993_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH Access via Empty Passwords
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitEmptyPasswords\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitEmptyPasswords\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitEmptyPasswords\s+
line: PermitEmptyPasswords no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80896-4
- CJIS-5.5.6
- DISA-STIG-RHEL-08-020330
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- sshd_disable_empty_passwords
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitEmptyPasswords no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "PermitEmptyPasswords no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable SSH Support for .rhosts Files
[ref]ruleSSH can emulate the behavior of the obsolete rsh
command in allowing users to enable insecure access to their
accounts via .rhosts files.
The default SSH configuration disables support for .rhosts . The appropriate
configuration is used if no value is set for IgnoreRhosts .
To explicitly disable support for .rhosts files, add or correct the following line in
/etc/ssh/sshd_config :
IgnoreRhosts yes Rationale:SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts. Identifiers:
CCE-80899-8 References:
11, 12, 14, 15, 16, 18, 3, 5, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3, FIA_UAU.1, SRG-OS-000480-GPOS-00227, SRG-OS-000107-VMM-000530, 5.2.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH Support for .rhosts Files
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*IgnoreRhosts\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*IgnoreRhosts\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*IgnoreRhosts\s+
line: IgnoreRhosts yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80899-8
- CJIS-5.5.6
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_rhosts
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*IgnoreRhosts\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "IgnoreRhosts yes" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "IgnoreRhosts yes" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable SSH Root Login
[ref]ruleThe root user should never be allowed to login to a
system directly over a network.
To disable root login via SSH, add or correct the following line in
/etc/ssh/sshd_config :
PermitRootLogin no Warning:
This rule is disabled on Red Hat Virtualization Hosts and Managers, it will report not applicable.
RHV hosts require root access to be managed by RHV Manager. Rationale:Even though the communications channel may be encrypted, an additional layer of
security is gained by extending the policy of not logging directly on as root.
In addition, logging in with a user-specific account provides individual
accountability of actions performed on the system and also helps to minimize
direct attack attempts on root's password. Identifiers:
CCE-80901-2 References:
BP28(R19), NT007(R21), 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.6, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.1.5, CCI-000366, CCI-000770, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-6(2), AC-17(a), IA-2, IA-2(5), CM-7(a), CM-7(b), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, FIA_UAU.1, SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000, RHEL-08-010550, 5.2.10, SV-230296r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH Root Login
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitRootLogin\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitRootLogin\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitRootLogin\s+
line: PermitRootLogin no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80901-2
- CJIS-5.5.6
- DISA-STIG-RHEL-08-010550
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(2)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-2
- NIST-800-53-IA-2(5)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_root_login
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitRootLogin no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "PermitRootLogin no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable SSH TCP Forwarding
[ref]ruleThe AllowTcpForwarding parameter specifies whether TCP forwarding is permitted.
To disable TCP forwarding, add or correct the following line in
/etc/ssh/sshd_config :
AllowTcpForwarding no Rationale:Leaving port forwarding enabled can expose the organization to security risks and back-doors. Identifiers:
CCE-83301-2 References:
5.2.17 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH TCP Forwarding
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*AllowTcpForwarding\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*AllowTcpForwarding\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*AllowTcpForwarding\s+
line: AllowTcpForwarding no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83301-2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_tcp_forwarding
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*AllowTcpForwarding\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "AllowTcpForwarding no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "AllowTcpForwarding no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable X11 Forwarding
[ref]ruleThe X11Forwarding parameter provides the ability to tunnel X11 traffic
through the connection to enable remote graphic connections.
SSH has the capability to encrypt remote X11 connections when SSH's
X11Forwarding option is enabled.
The default SSH configuration disables X11Forwarding. The appropriate
configuration is used if no value is set for X11Forwarding .
To explicitly disable X11 Forwarding, add or correct the following line in
/etc/ssh/sshd_config :
X11Forwarding no Rationale:Disable X11 forwarding unless there is an operational requirement to use X11
applications directly. There is a small risk that the remote X11 servers of
users who are logged in via SSH with X11 forwarding could be compromised by
other users on the X11 server. Note that even if X11 forwarding is disabled,
users can always install their own forwarders. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable X11 Forwarding
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*X11Forwarding\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*X11Forwarding\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*X11Forwarding\s+
line: X11Forwarding no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83360-8
- DISA-STIG-RHEL-08-040340
- NIST-800-53-CM-6(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_x11_forwarding
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*X11Forwarding\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "X11Forwarding no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "X11Forwarding no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Do Not Allow SSH Environment Options
[ref]ruleEnsure that users are not able to override environment variables of the SSH daemon.
The default SSH configuration disables environment processing. The appropriate
configuration is used if no value is set for PermitUserEnvironment .
To explicitly disable Environment options, add or correct the following
/etc/ssh/sshd_config :
PermitUserEnvironment no Rationale:SSH environment options potentially allow users to bypass
access restriction in some configurations. Identifiers:
CCE-80903-8 References:
11, 3, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, SRG-OS-000480-GPOS-00229, SRG-OS-000480-VMM-002000, RHEL-08-010830, 5.2.12, SV-230330r646870_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Do Not Allow SSH Environment Options
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitUserEnvironment\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitUserEnvironment\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitUserEnvironment\s+
line: PermitUserEnvironment no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-80903-8
- CJIS-5.5.6
- DISA-STIG-RHEL-08-010830
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_do_not_permit_user_env
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitUserEnvironment no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "PermitUserEnvironment no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable PAM
[ref]ruleUsePAM Enables the Pluggable Authentication Module interface. If set to “yes” this will
enable PAM authentication using ChallengeResponseAuthentication and
PasswordAuthentication in addition to PAM account and session module processing for all
authentication types.
To enable PAM authentication, add or correct the following line in
/etc/ssh/sshd_config :
UsePAM yes Rationale:When UsePAM is set to yes, PAM runs through account and session types properly. This is
important if you want to restrict access to services based off of IP, time or other factors of
the account. Additionally, you can make sure users inherit certain environment variables
on login or disallow access to the server. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Enable PAM
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*UsePAM\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*UsePAM\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*UsePAM\s+
line: UsePAM yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86721-8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_enable_pam
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*UsePAM\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "UsePAM yes" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "UsePAM yes" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure SSH LoginGraceTime is configured
[ref]ruleThe LoginGraceTime parameter to the SSH server specifies the time allowed for successful authentication to
the SSH server. The longer the Grace period is the more open unauthenticated connections
can exist. Like other session controls in this session the Grace Period should be limited to
appropriate limits to ensure the service is available for needed access. Rationale:Setting the LoginGraceTime parameter to a low number will minimize the risk of successful
brute force attacks to the SSH server. It will also limit the number of concurrent
unauthenticated connections. Identifiers:
CCE-86551-9 References:
5.2.14 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sshd_set_login_grace_time # promote to variable
set_fact:
var_sshd_set_login_grace_time: !!str 60
tags:
- always
- name: Ensure SSH LoginGraceTime is configured
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*LoginGraceTime\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*LoginGraceTime\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LoginGraceTime\s+
line: LoginGraceTime {{ var_sshd_set_login_grace_time }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-86551-9
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_login_grace_time
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_set_login_grace_time='60'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*LoginGraceTime\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "LoginGraceTime $var_sshd_set_login_grace_time" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "LoginGraceTime $var_sshd_set_login_grace_time" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set SSH Daemon LogLevel to VERBOSE
[ref]ruleThe VERBOSE parameter configures the SSH daemon to record login and logout activity.
To specify the log level in
SSH, add or correct the following line in
/etc/ssh/sshd_config :
LogLevel VERBOSE Rationale:SSH provides several logging levels with varying amounts of verbosity. DEBUG is specifically
not recommended other than strictly for debugging SSH communications since it provides
so much data that it is difficult to identify important security information. INFO or
VERBOSE level is the basic level that only records login activity of SSH users. In many
situations, such as Incident Response, it is important to determine when a particular user was active
on a system. The logout record can eliminate those users who disconnected, which helps narrow the
field. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Set SSH Daemon LogLevel to VERBOSE
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*LogLevel\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*LogLevel\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LogLevel\s+
line: LogLevel VERBOSE
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82420-1
- NIST-800-53-AC-17(1)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_loglevel_verbose
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*LogLevel\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "LogLevel VERBOSE" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "LogLevel VERBOSE" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set SSH authentication attempt limit
[ref]ruleThe MaxAuthTries parameter specifies the maximum number of authentication attempts
permitted per connection. Once the number of failures reaches half this value, additional failures are logged.
to set MaxAUthTries edit /etc/ssh/sshd_config as follows:
MaxAuthTries 4 Rationale:Setting the MaxAuthTries parameter to a low number will minimize the risk of successful
brute force attacks to the SSH server. Identifiers:
CCE-83500-9 References:
0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, 5.2.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_max_auth_tries_value # promote to variable
set_fact:
sshd_max_auth_tries_value: !!str 4
tags:
- always
- name: Set SSH authentication attempt limit
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*MaxAuthTries\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*MaxAuthTries\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxAuthTries\s+
line: MaxAuthTries {{ sshd_max_auth_tries_value }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83500-9
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_max_auth_tries
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_max_auth_tries_value='4'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*MaxAuthTries\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "MaxAuthTries $sshd_max_auth_tries_value" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "MaxAuthTries $sshd_max_auth_tries_value" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set SSH MaxSessions limit
[ref]ruleThe MaxSessions parameter specifies the maximum number of open sessions permitted
from a given connection. To set MaxSessions edit
/etc/ssh/sshd_config as follows: MaxSessions 4 Rationale:To protect a system from denial of service due to a large number of concurrent
sessions, use the rate limiting function of MaxSessions to protect availability
of sshd logins and prevent overwhelming the daemon. Identifiers:
CCE-83357-4 References:
5.2.19 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: XCCDF Value var_sshd_max_sessions # promote to variable
set_fact:
var_sshd_max_sessions: !!str 4
tags:
- always
- name: Set SSH MaxSessions limit
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*MaxSessions\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*MaxSessions\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxSessions\s+
line: MaxSessions {{ var_sshd_max_sessions }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83357-4
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- sshd_set_max_sessions
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_max_sessions='4'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*MaxSessions\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "MaxSessions $var_sshd_max_sessions" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "MaxSessions $var_sshd_max_sessions" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure SSH MaxStartups is configured
[ref]ruleThe MaxStartups parameter specifies the maximum number of concurrent
unauthenticated connections to the SSH daemon. Additional connections will be
dropped until authentication succeeds or the LoginGraceTime expires for a
connection. To confgure MaxStartups, you should add or correct the following
line in the
/etc/ssh/sshd_config file:
MaxStartups 10:30:60
CIS recommends a MaxStartups value of '10:30:60', or more restrictive where
dictated by site policy.Rationale:To protect a system from denial of service due to a large number of pending
authentication connection attempts, use the rate limiting function of MaxStartups
to protect availability of sshd logins and prevent overwhelming the daemon. Identifiers:
CCE-90718-8 References:
5.2.18 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sshd_set_maxstartups # promote to variable
set_fact:
var_sshd_set_maxstartups: !!str 10:30:60
tags:
- always
- name: Ensure SSH MaxStartups is configured
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*MaxStartups\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*MaxStartups\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxStartups\s+
line: MaxStartups {{ var_sshd_set_maxstartups }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90718-8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_maxstartups
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_set_maxstartups='10:30:60'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*MaxStartups\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "MaxStartups $var_sshd_set_maxstartups" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "MaxStartups $var_sshd_set_maxstartups" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns SSH Server config file
[ref]rule
To properly set the group owner of /etc/ssh/sshd_config , run the command:
$ sudo chgrp root /etc/ssh/sshd_config Rationale:Service configuration files enable or disable features of their respective
services that if configured incorrectly can lead to insecure and vulnerable
configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82901-0 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.2.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/ssh/sshd_config
stat:
path: /etc/ssh/sshd_config
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82901-0
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_sshd_config
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/ssh/sshd_config
file:
path: /etc/ssh/sshd_config
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-82901-0
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_groupowner_sshd_config
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /etc/ssh/sshd_config
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on SSH Server config file
[ref]rule
To properly set the owner of /etc/ssh/sshd_config , run the command:
$ sudo chown root /etc/ssh/sshd_config Rationale:Service configuration files enable or disable features of their respective
services that if configured incorrectly can lead to insecure and vulnerable
configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82898-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.2.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/ssh/sshd_config
stat:
path: /etc/ssh/sshd_config
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82898-8
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_sshd_config
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/ssh/sshd_config
file:
path: /etc/ssh/sshd_config
owner: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-82898-8
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_sshd_config
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chown 0 /etc/ssh/sshd_config
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on SSH Server config file
[ref]rule
To properly set the permissions of /etc/ssh/sshd_config , run the command:
$ sudo chmod 0600 /etc/ssh/sshd_config Rationale:Service configuration files enable or disable features of their respective
services that if configured incorrectly can lead to insecure and vulnerable
configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-82894-7 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.2.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/ssh/sshd_config
stat:
path: /etc/ssh/sshd_config
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82894-7
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_config
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /etc/ssh/sshd_config
file:
path: /etc/ssh/sshd_config
mode: u-xs,g-xwrs,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-82894-7
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_config
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xwrs,o-xwrt /etc/ssh/sshd_config
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on SSH Server Public *.pub Key Files
[ref]rule To properly set the permissions of /etc/ssh/*.pub , run the command: $ sudo chmod 0644 /etc/ssh/*.pub Rationale:If a public host key file is modified by an unauthorized user, the SSH service
may be compromised. Identifiers:
CCE-82428-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.13, 3.13.10, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, RHEL-08-010480, 5.2.4, SV-230286r627750_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find /etc/ssh/ file(s)
command: find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xws,o+xwt -type f -regex "^.*.pub$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82428-4
- DISA-STIG-RHEL-08-010480
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_pub_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/ssh/ file(s)
file:
path: '{{ item }}'
mode: u-xs,g-xws,o-xwt
state: file
with_items:
- '{{ files_found.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-82428-4
- DISA-STIG-RHEL-08-010480
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_pub_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
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# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xws,o+xwt -type f -regex '^.*.pub$' -exec chmod u-xs,g-xws,o-xwt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Puppet snippet: (show)
include ssh_public_key_perms
class ssh_public_key_perms {
exec { 'sshd_pub_key':
command => "chmod 0644 /etc/ssh/*.pub",
path => '/bin:/usr/bin'
}
}
|