Title

Ubuntu OS must disable the x86 Ctrl-Alt-Delete key sequence if a graphical user interface is installed. (Cat II impact)

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 Content

Verify Ubuntu OS 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 Text

Configure Ubuntu OS to disable the Ctrl-Alt-Delete sequence when using a graphical user interface. Create or edit a file named /etc/dconf/db/local.d/00-screensaver with the following contents: [org/gnome/settings-daemon/plugins/media-keys] logout="" Update the dconf settings: $ sudo dconf update

Additional Identifiers

Rule ID: SV-275630r1147940_rule

Vulnerability ID: V-275630

Group Title: SRG-OS-000480-GPOS-00227

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