RHEL 9 must not allow users to override SSH environment variables.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
|---|---|---|---|---|
| V-257993 | RHEL-09-255085 | SV-257993r943042_rule | Medium |
| Description |
|---|
| SSH environment options potentially allow users to bypass access restriction in some configurations. |
| STIG | Date |
|---|---|
| Red Hat Enterprise Linux 9 Security Technical Implementation Guide | 2023-12-01 |
Details
| Check Text ( C-61734r943041_chk ) |
|---|
| Verify that unattended or automatic logon via SSH is disabled with the following command: $ sudo grep -ir permituserenvironment /etc/ssh/sshd_config /etc/ssh/sshd_config.d/* PermitUserEnvironment no If "PermitUserEnvironment" is set to "yes", is missing completely, or is commented out, this is a finding. If the required value is not set, this is a finding. |
| Fix Text (F-61658r925965_fix) |
|---|
| Configure the RHEL 9 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 |