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V-258764

CAT II (Medium)

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

Rule ID

SV-258764r933353_rule

STIG

VMware vSphere 8.0 ESXi Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-000366

Discussion

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).

Check Content

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

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)