cis-gcp-cos-6-1-2

name	cis-gcp-cos-6.1.2
description	Ensure permissions on /etc/shadow are configured
category	cis-gcp-cos
version	1.2.0
author	cyberstrike-official
tags	["cis","gcp","container-optimized-os","file-permissions","shadow","system-files"]
cis_id	6.1.2
cis_benchmark	CIS Google Container-Optimized OS Benchmark v1.2.0
tech_stack	["gcp","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

6.1.2 Ensure permissions on /etc/shadow are configured (Automated)

Description

The /etc/shadow file is used to store the information about user accounts that is critical to the security of those accounts, such as the hashed password and other security information.

Rationale

If attackers can gain read access to the /etc/shadow file, they can easily run a password cracking program against the hashed password to break it. Other security information that is stored in the /etc/shadow file (such as expiration) could also be useful to subvert the user accounts.

Audit Procedure

Run the following command and verify verify Uid is 0/root, Gid is 0/root or <gid>/shadow, and Access is 640 or more restrictive:

# stat /etc/shadow
Access: (0640/-rw-r-----)  Uid: (    0/    root)   Gid: (    0/    root)

Expected Result

Uid should be 0/root, Gid should be 0/root or <gid>/shadow, and Access should be 640 or more restrictive.

Remediation

Run the one of the following chown commands as appropriate and the chmod to set permissions on /etc/shadow:

# chown root:root /etc/shadow
# chown root:shadow /etc/shadow

# chmod o-rwx,g-wx /etc/shadow

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	3.3 Configure Data Access Control Lists	x	x	x
v7	16.4 Encrypt or Hash all Authentication Credentials		x	x

Profile

• Level 1 - Server