TOSS must disable the user list at logon for graphical user interfaces.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-252964	TOSS-04-020250	SV-252964r824216_rule		Medium

Description
Leaving the user list enabled is a security risk since it allows anyone with physical access to the system to enumerate known user accounts without authenticated access to the system.

STIG	Date
Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide	2022-08-29

Details

Check Text ( C-56417r824214_chk )
Verify the operating system disables the user logon list for graphical user interfaces with the following command: Note: This requirement assumes the use of the TOSS default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ sudo gsettings get org.gnome.login-screen disable-user-list true If the setting is "false", this is a finding.

Check Text ( C-56417r824214_chk )

Verify the operating system disables the user logon list for graphical user interfaces with the following command:

Note: This requirement assumes the use of the TOSS default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable.

$ sudo gsettings get org.gnome.login-screen disable-user-list
true

If the setting is "false", this is a finding.

Fix Text (F-56367r824215_fix)
Configure the operating system to disable the user list at logon for graphical user interfaces. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory. $ sudo touch /etc/dconf/db/local.d/02-login-screen [org/gnome/login-screen] disable-user-list=true Update the system databases: $ sudo dconf update

Fix Text (F-56367r824215_fix)

Configure the operating system to disable the user list at logon for graphical user interfaces.

Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command:
Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory.

$ sudo touch /etc/dconf/db/local.d/02-login-screen

[org/gnome/login-screen]
disable-user-list=true

Update the system databases:
$ sudo dconf update