cis-gcp-cos-6-1-6

name	cis-gcp-cos-6.1.6
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	6.1.6
cis_benchmark	CIS Google Container-Optimized OS Benchmark v1.2.0
tech_stack	["gcp","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

6.1.6 Ensure permissions on /etc/shadow- are configured (Automated)

Description

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

Rationale

It is critical to ensure that the /etc/shadow- file is protected from unauthorized access. Although it is protected by default, the file permissions could be changed either inadvertently or through malicious actions.

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-rw /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 2 - Server