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 22.04 LTS must remain in place until the user reauthenticates. No other activity aside from reauthentication must unlock the system.

Check

Verify Ubuntu 22.04 LTS has a graphical user interface session lock configured to activate after 15 minutes of inactivity by using the following commands:

Note: If no graphical user interface is installed, this requirement is not applicable.

Get the following settings to verify the graphical user interface session is configured to lock the graphical user session after 15 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 900

If "lock-enabled" is not set to "true", is commented out, or is missing, 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 "900", is commented out, or is missing, this is a finding.

Fix

Configure Ubuntu 22.04 LTS to lock the current graphical user interface session after 15 minutes of inactivity.

Set the following settings to allow graphical user interface session lock to initiate after 15 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 900