The ESXi host Secure Shell (SSH) daemon must not permit tunnels.
An XCCDF Rule
Description
<VulnDiscussion>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).</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-256393r885960_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
From an ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":
PermitTunnel no