Vulnerability Discussion

It is critical that when RHEL 8 is at risk of failing to process audit logs as required, it takes action to mitigate the failure. Audit processing failures include software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode.

When availability is an overriding concern, other approved actions in response to an audit failure are as follows:

1) If the failure was caused by the lack of audit record storage capacity, RHEL 8 must continue generating audit records if possible (automatically restarting the audit service if necessary) and overwriting the oldest audit records in a first-in-first-out manner.

2) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, RHEL 8 must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server.

Check

Verify that the SA and ISSO (at a minimum) are notified when the audit storage volume is full.

Check which action RHEL 8 takes when the audit storage volume is full with the following command:

$ sudo grep max_log_file_action /etc/audit/auditd.conf

max_log_file_action=syslog

If the value of the "max_log_file_action" option is set to "ignore", "rotate", or "suspend", or the line is commented out, ask the system administrator to indicate how the system takes appropriate action when an audit storage volume is full. If there is no evidence of appropriate action, this is a finding.

Fix

Configure RHEL 8 to notify the System Administrator (SA) and Information System Security Officer (ISSO) when the audit storage volume is full by configuring the "max_log_file_action" parameter in the "/etc/audit/auditd.conf" file with the a value of "syslog" or "keep_logs":

max_log_file_action = syslog