cis-ubuntu1804-v220-4-5-3

name	cis-ubuntu1804-v220-4-5-3
description	Ensure default group for the root account is GID 0
category	cis-iam
version	2.2.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-18.04","users","account-security"]
cis_id	4.5.3
cis_benchmark	CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 - Control 4.5.3

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Description

The usermod command can be used to specify which group the root user belongs to. This affects permissions of files that are created by the root user.

Rationale

Using GID 0 for the root account helps prevent root-owned files from accidentally becoming accessible to non-privileged users.

Audit Procedure

Command Line

Run the following command and verify the result is 0:

grep "^root:" /etc/passwd | cut -f4 -d:

Expected Result

0

Remediation

Command Line

Run the following command to set the root user default group to GID 0:

usermod -g 0 root

References

1. NIST SP 800-53 Rev. 5: CM-1, CM-2, CM-6, CM-7, IA-5

CIS Controls

v8 - 3.3 Configure Data Access Control Lists - Configure data access control lists based on a user's need to know.

v7 - 14.6 Protect Information through Access Control Lists.

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Assessment Status

Automated