SV-252915r1016299: TOSS must not permit direct logons to the root account using remote access from outside of the system via SSH. | Tri-Lab Operating System Stack (TOSS) 4 STIG SCAP Benchmark

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Assessment Title

Rule Text

TOSS must not permit direct logons to the root account using remote access from outside of the system via SSH.

Description

Discussion Text

Even though the communications channel may be encrypted, an additional layer of security is gained by extending the policy of not logging on directly as root. In addition, logging on with a user-specific account provides individual accountability of actions performed on the system.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-004045Not mappedCCI-000770

References

DPMS Target TOSS 4 DISA DPMS Target TOSS 4 5469

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.stig.toss4os:def:252915
# TOSS must not permit direct logons to the root account using remote access from outside of the system via SSH.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# /etc/ssh/sshd_config:PermitRootLogin == no
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  ( (sed -En 's/^\s*(?i)PermitRootLogin(?-i)[ \t]+([\w\"]+)[\s]*(?:|(?:#.*))?$/\1/p' '/etc/ssh/sshd_config') | grep -Pq '^(no|"no")$' ) || ( (grep -rhP --include='*' '^\s*(?i)PermitRootLogin(?-i)[ \t]+([\w\"]+)[\s]*(?:|(?:#.*))?$' '/etc/ssh/sshd_config.d' | sed -En 's/^\s*(?i)PermitRootLogin(?-i)[ \t]+([\w\"]+)[\s]*(?:|(?:#.*))?$/\1/p') | grep -Pq '^(no|"no")$' )
}

if test_1; then
  echo "PASS"
else
  echo "FAIL"
fi

Assessment Script Powered by AISandbox-executed

A standalone Shell script to assess this control automatically. Review before running it in your environment.

Syntax-checked and actually executed in an isolated sandbox (not the real system this checks) — confirmed to run without errors.

#!/bin/sh
# oval:mil.disa.stig.toss4os:def:252915
if [ ! -f "/etc/ssh/sshd_config" ]; then echo "PASS"; exit 0; fi
content=$(grep -E "^\\s*(?i)PermitRootLogin(?-i)[ \\t]+([\\w\\\"]+)[\\s]*(?:|(?:#.*))?$" /etc/ssh/sshd_config)
if [[ $content =~ ^(no|"no")$ ]]; then echo "PASS"; exit 0; fi
echo "FAIL"; exit 1

Remediation

Configure TOSS to stop users from logging on remotely from outside of the cluster as the "root" user via SSH.

Edit the appropriate "/etc/ssh/sshd_config" file to uncomment or add the line for the "PermitRootLogin" keyword and set its value to "no":

PermitRootLogin no

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