cyberstrikeus CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Control 5.3.20
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.
Impact
If UsePAM is enabled, you will not be able to run sshd(5) as a non-root user.
Audit Procedure
Command Line
Run the following command and verify that output matches:
sshd -T -C user=root -C host="$(hostname)" -C addr="$(grep $(hostname) /etc/hosts | awk '{print $1}')" | grep -i usepam
Expected Result
usepam yes
Run the following command and verify the output:
grep -Ei '^\s*UsePAM\s+no' /etc/ssh/sshd_config
Nothing should be returned.
Remediation
Command Line
Edit the /etc/ssh/sshd_config file to set the parameter as follows:
UsePAM yes
Default Value
usePAM yes
References
- SSHD_CONFIG(5)
CIS Controls
Version 7
5.1 Establish Secure Configurations - Maintain documented, standard security configuration standards for all authorized operating systems and software.
Profile Applicability
- Level 1 - Server
- Level 1 - Workstation
Assessment Status
Automated