Vulnerability Discussion

A locally logged-on user who presses Ctrl-Alt-Delete, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of a mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot. In the graphical environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken.

Check

Verify Ubuntu 22.04 LTS is not configured to reboot the system when Ctrl-Alt-Delete is pressed when using a graphical user interface by using the following command:

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

$ gsettings get org.gnome.settings-daemon.plugins.media-keys logout
@as []

If the "logout" key is bound to an action, is commented out, or is missing, this is a finding.

Fix

Configure Ubuntu 22.04 LTS to disable the Ctrl-Alt-Delete sequence when using a graphical user interface.

$ gsettings set org.gnome.settings-daemon.plugins.media-keys logout []

Update the dconf settings:

# dconf update