The audit system must be configured to audit all discretionary access control permission modifications.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-29274	GEN002820-11	SV-64617r1_rule	ECAR-1 ECAR-2 ECAR-3	Medium

Description
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.

STIG	Date
Oracle Linux 5 Security Technical Implementation Guide	2015-06-05

Details

Check Text ( C-53027r1_chk )
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 (F-55207r2_fix)
The "-F 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=" 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= -S removexattr Restart the auditd service. # service auditd restart

Fix Text (F-55207r2_fix)

The "-F 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=" 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= -S removexattr

Restart the auditd service.
# service auditd restart