The ESXi host Secure Shell (SSH) daemon must be configured to not allow gateway ports.

SSH Transmission Control Protocol (TCP) connection forwarding provides a mechanism to establish TCP connections proxied by the SSH server. This function can provide convenience similar to a virtual private network (VPN) with the similar risk of providing a path to circumvent firewalls and network Access Control Lists (ACLs). Gateway ports allow remote forwarded ports to bind to nonloopback addresses on the server.

From an ESXi shell, run the following command:

# esxcli system ssh server config list -k gatewayports

or

From a PowerCLI command prompt while connected to the ESXi host, run the following commands:

$esxcli = Get-EsxCli -v2 $esxcli.system.ssh.server.config.list.invoke() | Where-Object {$_.Key -eq 'gatewayports'}

Example result:

gatewayports no

If "gatewayports" is not configured to "no", this is a finding.

From an ESXi shell, run the following command:

# esxcli system ssh server config set -k gatewayports -v no

or

From a PowerCLI command prompt while connected to the ESXi host, run the following commands:

$esxcli = Get-EsxCli -v2 $arguments = $esxcli.system.ssh.server.config.set.CreateArgs() $arguments.keyword = 'gatewayports' $arguments.value = 'no' $esxcli.system.ssh.server.config.set.Invoke($arguments)