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

From VMware ESXi Server 5.0 Security Technical Implementation Guide

Associated with: CCI-000366

SV-51067r2_rule The SSH client 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

Disable lock down mode. Enable the ESXi Shell. Check the SSH client configuration for the gateway ports setting. # grep -i GatewayPorts /etc/ssh/ssh_config | grep -v '^#' If "GatewayPorts" is set to "yes", this is a finding. If the /etc/ssh/ssh_config file does not exist, this is not a finding. Re-enable lock down mode.

Fix text

Disable lock down mode. Enable the ESXi Shell. Edit the SSH client configuration and add/modify the "GatewayPorts" configuration, setting it to "no". # vi /etc/ssh/ssh_config Re-enable lock down mode.

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