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-256392r885957_rule		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	2023-06-21

Details

Check Text ( C-60067r885955_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