cis-ubuntu1804-v220-2-2-7

name	cis-ubuntu1804-v220-2-2-7
description	Ensure DNS Server is not installed
category	cis-networking
version	2.2.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-18.04","services","dns"]
cis_id	2.2.7
cis_benchmark	CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

2.2.7 Ensure DNS Server is not installed (Automated)

Profile

• Level 1 - Server
• Level 1 - Workstation

Description

The Domain Name System (DNS) is a hierarchical naming system that maps names to IP addresses for computers, services and other resources connected to a network.

Rationale

Unless a system is specifically designated to act as a DNS server, it is recommended that the package be deleted to reduce the potential attack surface.

Audit Procedure

Command Line

Run the following command to verify DNS server is not installed:

# dpkg-query -s bind9 &>/dev/null && echo "bind9 is installed"

Nothing should be returned.

Expected Result

No output (empty result).

Remediation

Command Line

Run the following commands to disable DNS server:

# apt purge bind9

References

1. NIST SP 800-53 Rev. 5: CM-7

CIS Controls

• 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