Vulnerability Discussion

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence.

The session lock is implemented at the point where session activity can be determined.

Regardless of where the session lock is determined and implemented, once invoked, a session lock of Ubuntu 24.04 LTS must remain in place until the user reauthenticates. No other activity aside from reauthentication must unlock the system.

Check

Note: If Ubuntu 24.04 LTS does not have a graphical user interface installed, this requirement is not applicable.

Verify the Ubuntu operation system has a graphical user interface session lock configured to activate after 10 minutes of inactivity with the following commands:

Set the following settings to verify the graphical user interface session is configured to lock the graphical user session after 10 minutes of inactivity:

**$ gsettings get org.gnome.desktop.screensaver lock-enabled
true

$ gsettings get org.gnome.desktop.screensaver lock-delay
uint32 0

$ gsettings get org.gnome.desktop.session idle-delay
uint32 600

Note: If "lock-enabled" is not set to "true", this is a finding.

If "lock-delay" is set to a value greater than "0", or if "idle-delay" is set to a value greater than "600", or either settings are missing, this is a finding.

Fix

Configure Ubuntu 24.04 LTS to lock the current graphical user interface session after 10 minutes of inactivity.

Set the following settings to allow graphical user interface session lock to initiate after 10 minutes of inactivity:

$ gsettings set org.gnome.desktop.screensaver lock-enabled true
$ gsettings set org.gnome.desktop.screensaver lock-delay 0
$ gsettings set org.gnome.desktop.session idle-delay 600