The ESXi host Secure Shell (SSH) daemon must not permit tunnels.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-258764	ESXI-80-000209	SV-258764r933353_rule		Medium

Description
OpenSSH has the ability to create network tunnels (layer 2 and layer 3) over an SSH connection. 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 Access Control Lists (ACLs).

STIG	Date
VMware vSphere 8.0 ESXi Security Technical Implementation Guide	2023-10-11

Details

Check Text ( C-62504r933351_chk )
From an ESXi shell, run the following command: # esxcli system ssh server config list -k permittunnel 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 'permittunnel'} Example result: permittunnel no If "permittunnel" is not configured to "no", this is a finding.

Check Text ( C-62504r933351_chk )

From an ESXi shell, run the following command:

# esxcli system ssh server config list -k permittunnel

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 'permittunnel'}

Example result:

permittunnel no

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

Fix Text (F-62413r933352_fix)
From an ESXi shell, run the following command: # esxcli system ssh server config set -k permittunnel -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 = 'permittunnel' $arguments.value = 'no' $esxcli.system.ssh.server.config.set.Invoke($arguments)

Fix Text (F-62413r933352_fix)

From an ESXi shell, run the following command:

# esxcli system ssh server config set -k permittunnel -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 = 'permittunnel'
$arguments.value = 'no'
$esxcli.system.ssh.server.config.set.Invoke($arguments)