Title

The audit system must be configured to audit all discretionary access control permission modifications. (Cat II impact)

Discussion

If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise.

Check Content

Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i " removexattr " If "-S removexattr" is not in the result, this is a finding.

Fix Text

The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S removexattr Restart the auditd service. # rcauditd restart OR # service auditd restart

Additional Identifiers

Rule ID: SV-45342r1_rule

Vulnerability ID: V-29274

Group Title: GEN002820-11

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.