Remove the GDM Package Group

Documentos > Datadog Security > OOTB Rules > Remove the GDM Package Group

This page is not yet available in Spanish. We are working on its translation.
If you have any questions or feedback about our current translation project, feel free to reach out to us!

Description

By removing the gdm3 package, the system no longer has GNOME installed

installed. If X Windows is not installed then the system cannot boot into graphical user mode. This prevents the system from being accidentally or maliciously booted into a graphical.target mode. To do so, run the following command:

$ sudo apt remove gdm3

Rationale

Unnecessary service packages must not be installed to decrease the attack surface of the system. A graphical environment is unnecessary for certain types of systems including a virtualization hypervisor.

Remediation

Shell script

The following script can be run on the host to remediate the issue.

#!/bin/bash

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed; then

# CAUTION: This remediation script will remove gdm3
#	   from the system, and may remove any packages
#	   that depend on gdm3. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

DEBIAN_FRONTEND=noninteractive apt-get remove -y "gdm3"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Ansible playbook

The following playbook can be run with Ansible to remediate the issue.

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_gdm_removed

- name: Ensure gdm3 is removed
  package:
    name: gdm3
    state: absent
  when: '"gdm3" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_gdm_removed