cis-ubuntu2004-v300-1-7-1

name	cis-ubuntu2004-v300-1-7-1
description	Ensure GDM is removed
category	cis-networking
version	3.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-20.04","gnome","gdm","attack-surface"]
cis_id	1.7.1
cis_benchmark	CIS Ubuntu Linux 20.04 LTS Benchmark v3.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

1.7.1 Ensure GDM is removed (Automated)

Profile

• Level 2 - Server

Description

The GNOME Display Manager (GDM) is a program that manages graphical display servers and handles graphical user logins.

Rationale

If a Graphical User Interface (GUI) is not required, it should be removed to reduce the attack surface of the system.

Impact

Removing the GNOME Display manager will remove the Graphical User Interface (GUI) from the system.

Audit Procedure

Command Line

Run the following command and verify gdm3 is not installed:

# dpkg-query -s gdm3 &>/dev/null && echo "gdm3 is installed"

Nothing should be returned.

Expected Result

No output should be returned, confirming gdm3 is not installed.

Remediation

Command Line

Run the following commands to uninstall gdm3 and remove unused dependencies:

# apt purge gdm3
# apt autoremove gdm3

References

1. NIST SP 800-53 Rev. 5: CM-11

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	4.8 Uninstall or Disable Unnecessary Services on Enterprise Assets and Software		*	*
v7	9.2 Ensure Only Approved Ports, Protocols and Services Are Running		*	*

MITRE ATT&CK Mappings: T1543, T1543.002 | TA0002 | M1033