Ubuntu OS must retain a user's session lock until that user reestablishes access using established identification and authentication procedures.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-275628	SRG-OS-000028-GPOS-00009	RIIM-OS-271020	SV-275628r1147934_rule	2025-10-02	1

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

Description

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

ℹ️ Check
Verify Ubuntu OS has a graphical user interface session lock enabled by using the following command: Note: If no graphical user interface is installed, this requirement is not applicable. $ sudo gsettings get org.gnome.desktop.screensaver lock-enabled true If "lock-enabled" is not set to "true", is commented out, or is missing, this is a finding.

✔️ Fix
Configure Ubuntu OS to allow a user to lock the current graphical user interface session. Create or edit a file named /etc/dconf/db/local.d/00-screensaver with the following contents: [org/gnome/desktop/screensaver] lock-enabled=true