AlmaLinux OS 9 must not allow users to override SSH environment variables.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-269439 | ALMA-09-043030 | SV-269439r1050322_rule | CCI-002420 | medium |
| Description | ||||
| SSH environment options potentially allow users to bypass access restriction in some configurations. | ||||
| STIG | Date | |||
| CloudLinux AlmaLinux OS 9 Security Technical Implementation Guide | 2025-05-22 | |||
Details
Check Text (C-269439r1050322_chk)
Verify the SSH daemon prevents users from overriding SSH environment variables with the following command:
$ sshd -T | grep permituserenvironment
permituserenvironment no
If the "PermitUserEnvironment" keyword is set to "yes", or no output is returned, this is a finding.
Fix Text (F-73371r1048694_fix)
To configure the system to prevent users from overriding SSH environment variables, add or modify the following line in "/etc/ssh/sshd_config":
PermitUserEnvironment no
Alternatively, add the setting to an include file if the line "Include /etc/ssh/sshd_config.d/*.conf" is found at the top of the "/etc/ssh/sshd_config" file:
$ echo "PermitUserEnvironment no" > /etc/ssh/sshd_config.d/environment.conf
Restart the SSH daemon for the settings to take effect:
$ systemctl restart sshd.service