Information
The GNOME Display Manager (GDM) is a program that manages graphical display servers and handles graphical user logins.
If a Graphical User Interface (GUI) is not required, it should be removed to reduce the attack surface of the system.
Solution
Run the following commands to uninstall gdm3 and remove unused dependencies:
# apt purge gdm3
# apt autoremove gdm3
Impact:
Removing the GNOME Display manager will remove the Graphical User Interface (GUI) from the system.