The SSH client must be configured to not allow TCP forwarding.

From VMware ESXi Server 5.0 Security Technical Implementation Guide

Part of GEN005516

Associated with: CCI-000366

SV-51065r3_rule The SSH client must be configured to not allow TCP forwarding.

Vulnerability discussion

SSH TCP connection forwarding provides a mechanism to establish TCP connections proxied by the SSH server. This function can provide similar convenience to a Virtual Private Network (VPN) with the similar risk of providing a path to circumvent firewalls and network ACLs.

Check content

Disable lock down mode. Enable the ESXi Shell. Execute the following command(s): # grep Forward /etc/ssh/ssh_config Re-enable lock down mode. If any of the following attributes (ForwardAgent, ForwardX11, or ForwardX11Trusted) exist and are not set to "no", this is a finding. If the /etc/ssh/ssh_config file does not exist, this is not a finding.

Fix text

Disable lock down mode. Enable the ESXi Shell. Execute the following command(s): # vi /etc/ssh/ssh_config Add/modify the attribute line entry to the following (quotes for emphasis only): "ForwardAgent no" "ForwardX11 no" "ForwardX11Trusted no" Re-enable lock down mode.

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.

Powered by sagemincer