Information
The operating system must disable the user list at logon for graphical user interfaces.
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.
Solution
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 "gdm" 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.
#!/usr/bin/env bash
{
if ! grep -P -- '^\h*\[org/gnome/login-screen\]\h*$', then
printf '\n%s' "[org/gnome/login-screen]" "disable-user-list=true" >> /etc/dconf/db/gdm.d/00-login-screen
else
printf '\n%s\n' "disable-user-list=true" >> /etc/dconf/db/gdm.d/00-login-screen
fi
}
Update the system databases:
# dconf update