The SSH daemon must be configured to not allow X11 forwarding.

From VMware vSphere ESXi 6.0 Security Technical Implementation Guide

Part of SRG-OS-000480-VMM-002000

Associated with: CCI-000366

SV-77705r1_rule The SSH daemon must be configured to not allow X11 forwarding.

Vulnerability discussion

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.

Check content

To verify the X11Forwarding setting, run the following command: # grep -i "^X11Forwarding" /etc/ssh/sshd_config If there is no output or the output is not exactly "X11Forwarding no", this is a finding.

Fix text

To set the X11Forwarding setting, add or correct the following line in "/etc/ssh/sshd_config": X11Forwarding no

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.