cis-ubuntu1804-v220-4-2-21

name	cis-ubuntu1804-v220-4-2-21
description	Ensure sshd UsePAM is enabled
category	cis-networking
version	2.2.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-18.04","ssh","remote-access"]
cis_id	4.2.21
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 4.2.21

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Description

UsePAM enables the Pluggable Authentication Module interface. If set to yes this will enable PAM authentication using ChallengeResponseAuthentication and PasswordAuthentication in addition to PAM account and session module processing for all authentication types.

Rationale

When usePAM is set to yes, PAM runs through account and session types properly. This is important if you want to restrict access to services based off of IP, time or other factors of the account. Additionally, you can make sure users inherit certain environment variables on login or disallow access to the server.

Audit Procedure

Command Line

Run the following command and verify the output:

sshd -T | grep -i usepam

Expected Result

usepam yes

Remediation

Command Line

Edit the /etc/ssh/sshd_config file to set the parameter as follows:

UsePAM yes

Default Value

UsePAM yes

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.

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Assessment Status

Automated