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CIS Ubuntu 14.04 LTS - 4.1.7 Ensure events that modify the system's Mandatory Access Controls are collected

DevOps & Security
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Collect audit events for modifications to SELinux/AppArmor mandatory access controls

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4.1.7 Ensure events that modify the system's Mandatory Access Controls are collected (Scored)

Profile Applicability

  • Level 2 - Server
  • Level 2 - Workstation

Description

Monitor SELinux/AppArmor mandatory access controls. The parameters below monitor any write access (potential additional, deletion or modification of files in the directory) or attribute changes to the /etc/selinux or /etc/apparmor and /etc/apparmor.d directories.

Rationale

Changes to files in these directories could indicate that an unauthorized user is attempting to modify access controls and change security contexts, leading to a compromise of the system.

Audit Procedure

On systems using SELinux run the following commands:

grep MAC-policy /etc/audit/audit.rules
auditctl -l | grep MAC-policy

Verify output of both matches:

-w /etc/selinux/ -p wa -k MAC-policy
-w /usr/share/selinux/ -p wa -k MAC-policy

On systems using AppArmor run the following commands:

grep MAC-policy /etc/audit/audit.rules
auditctl -l | grep MAC-policy

Verify output of both matches:

-w /etc/apparmor/ -p wa -k MAC-policy
-w /etc/apparmor.d/ -p wa -k MAC-policy

Expected Result

The audit rules for MAC-policy should be present and active.

Remediation

On systems using SELinux add the following line to the /etc/audit/audit.rules file:

-w /etc/selinux/ -p wa -k MAC-policy
-w /usr/share/selinux/ -p wa -k MAC-policy

On systems using AppArmor add the following line to the /etc/audit/audit.rules file:

-w /etc/apparmor/ -p wa -k MAC-policy
-w /etc/apparmor.d/ -p wa -k MAC-policy

Notes: Reloading the auditd config to set active settings may require a system reboot.

Default Value

Not configured by default.

References

  1. CIS Controls v6.1 - 3.6 Implement Automated Configuration Monitoring System

Profile

  • Level 2 - Server
  • Level 2 - Workstation