The ESXi host Secure Shell (SSH) daemon must be configured to not allow X11 forwarding.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-256392 | ESXI-70-000023 | SV-256392r959010_rule | CCI-000366 | medium |
| Description | ||||
| X11 forwarding over SSH allows for the secure remote execution of X11-based applications. This feature can increase the attack surface of an SSH connection. | ||||
| STIG | Date | |||
| VMware vSphere 7.0 ESXi Security Technical Implementation Guide | 2025-02-11 | |||
Details
Check Text (C-256392r959010_chk)
From an ESXi shell, run the following command:
# /usr/lib/vmware/openssh/bin/sshd -T|grep x11forwarding
Expected result:
x11forwarding no
If the output does not match the expected result, this is a finding.
Fix Text (F-60010r885956_fix)
From an ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":
X11Forwarding no