Title

The macOS system must provide an immediate warning to the System Administrator (SA) and Information System Security Officer (ISSO) (at a minimum) when allocated audit record storage volume reaches 75 percent of repository maximum audit record storage capacity. (Cat II impact)

Discussion

The audit service must be configured to require a minimum percentage of free disk space in order to run. This ensures that audit will notify the administrator that action is required to free up more disk space for audit logs. When "minfree" is set to 25 percent, security personnel are notified immediately when the storage volume is 75 percent full and are able to plan for audit record storage capacity expansion.

Check Content

The check displays the "% free" to leave available for the system. The audit system will not write logs if the volume has less than this percentage of free disk space. To view the current setting, run the following command: /usr/bin/sudo /usr/bin/grep ^minfree /etc/security/audit_control If this returns no results, or does not contain "25", this is a finding.

Fix Text

Edit the "/etc/security/audit_control" file and change the value for "minfree" to "25" using the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/.*minfree.*/minfree:25/' /etc/security/audit_control; /usr/bin/sudo /usr/sbin/audit -s A text editor may also be used to implement the required updates to the "/etc/security/audit_control file".

Additional Identifiers

Rule ID: SV-252474r877389_rule

Vulnerability ID: V-252474

Group Title: SRG-OS-000343-GPOS-00134

Expert Comments

CCIs tied to check.

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