Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide

The Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide (V2 R7) has 226 STIG checks. New to STIG checklists? Read What is a STIG checklist?, CKL vs CKLB, and STIG vs SCAP benchmark.

Find STIG checks

226STIG checks

Search filters this STIG's checks locally. Separate terms must all match (use quotes for an exact phrase). A search you ran on the Search page carries over here.

Severity

Version

V2 · R7

CurrentPublished Wed Sep 30 2026

The TOSS SSH daemon must perform strict mode checking of home directory configuration files.

Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide

Assessment Title

Rule Text

The TOSS SSH daemon must perform strict mode checking of home directory configuration files.

Description

Discussion Text

If other users have access to modify user-specific SSH configuration files, they may be able to log on to the system as another user.

New to STIG checklists? Read What is a STIG checklist? and CKL vs CKLB.

Objective

V-253106

Rule

SV-253106r991589_rule

Severity

medium

Rule Version

TOSS-04-040650

Documentable

false

IA Controls

NIST SP 800-53

Rev 5

Assessment Procedure

Check Text

Verify the SSH daemon performs strict mode checking of home directory configuration files with the following command:

$ sudo grep -i strictmodes /etc/ssh/sshd_config

StrictModes yes

If "StrictModes" is set to "no", is missing, or the returned line is commented out, this is a finding.

Implementation Procedure

Fix Text

Configure SSH to perform strict mode checking of home directory configuration files. Uncomment the "StrictModes" keyword in "/etc/ssh/sshd_config" and set the value to "yes":

StrictModes yes

The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command:

$ sudo systemctl restart sshd.service

STIG check 194 of 226 in the Tri-Lab Operating System Stack (TOSS) 4 STIG checklist

← Previous · V-253105The TOSS file integrity tool must be configured to verify extended attributes.Next · V-253107 →The TOSS SSH private host key files must have mode 0600 or less permissive.