The SSH daemon must be configured to not allow gateway ports.

From VMware vSphere ESXi 6.0 Security Technical Implementation Guide

Part of SRG-OS-000480-VMM-002000

Associated with: CCI-000366

SV-77703r1_rule The SSH daemon must be configured to not allow gateway ports.

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. Gateway ports allow remote forwarded ports to bind to non-loopback addresses on the server.

Check content

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

Fix text

To set the GatewayPorts setting, add or correct the following line in "/etc/ssh/sshd_config": GatewayPorts 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.