Vulnerability Discussion

If security personnel are not notified immediately when storage volume reaches 75% utilization, they are unable to plan for audit record storage capacity expansion.

Check

Verify the Ubuntu operating system notifies the System Administrator (SA) and Information System Security Officer (ISSO) (at a minimum) when allocated audit record storage volume reaches 75% of the repository maximum audit record storage capacity.

Check that the Ubuntu operating system notifies the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75% of the repository maximum audit record storage capacity with the following command:

# sudo grep ^space_left_action /etc/audit/auditd.conf

space_left_action email

# sudo grep ^space_left /etc/audit/auditd.conf

space_left 250000

If the "space_left" parameter is missing, set to blanks or set to a value less than 25% of the space free in the allocated audit record storage, this is a finding.

If the "space_left_action" parameter is missing or set to blanks, this is a finding.

If the "space_left_action" is set to "syslog", the system logs the event, but does not generate a notification, so this is a finding.

If the "space_left_action" is set to "exec", the system executes a designated script. If this script informs the SA of the event, this is not a finding.

If the "space_left_action" is set to "email" check the value of the "action_mail_acct" parameter with the following command:

# sudo grep action_mail_acct /etc/audit/auditd.conf

action_mail_acct root@localhost

The "action_mail_acct" parameter, if missing, defaults to "root". If the "action_mail_acct parameter" is not set to the e-mail address of the system administrator(s) and/or ISSO, this is a finding.

Note: If the email address of the system administrator is on a remote system a mail package must be available.

Fix

Edit /etc/audit/auditd.conf and set the space_left_action parameter to "exec" or "email".

If the space_left_action parameter is set to "email" set the action_mail_acct parameter to an e-mail address for the System Administrator (SA) and Information System Security Officer (ISSO).

If the space_left_action parameter is set to "exec", make sure the command being execute notifies the System Administrator (SA) and Information System Security Officer (ISSO).

Edit /etc/audit/auditd.conf and set the space_left parameter to be, at least, 25% of the repository maximum audit record storage capacity.