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V-282758

CAT II (Medium)

TOSS 5 must not allow users to override SSH environment variables.

Rule ID

SV-282758r1201254_rule

STIG

Tri-Lab Operating System Stack (TOSS) 5 Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-000366

Discussion

SSH environment options potentially allow users to bypass access restriction in some configurations.

Check Content

Verify unattended or automatic logon via SSH is disabled using the following command:

$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*permituserenvironment'

PermitUserEnvironment no

If "PermitUserEnvironment" is set to "yes", is missing completely, or is commented out, this is a finding.

Fix Text

Configure the TOSS 5 SSH daemon to not allow unattended or automatic logon to the system.

Add or edit the following line in the "/etc/ssh/sshd_config" file:

PermitUserEnvironment no

Restart the SSH daemon for the setting to take effect:

$ sudo systemctl restart sshd.service