The SSH daemon must not permit tunnels.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
|---|---|---|---|---|
| GEN005531-ESXI5-000108 | GEN005531-ESXI5-000108 | GEN005531-ESXI5-000108_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 ACLs. |
| STIG | Date |
|---|---|
| VMware ESXi v5 Security Technical Implementation Guide | 2013-01-15 |
Details
| Check Text ( C-GEN005531-ESXI5-000108_chk ) |
|---|
| Disable lock down mode. Enable the ESXi Shell. Login as root and execute the following command(s): # grep PermitTunnel /etc/ssh/sshd_config If "PermitTunnel" is set to "yes" or the keyword/line is missing, this is a finding. Re-enable lock down mode. |
| Fix Text (F-GEN005531-ESXI5-000108_fix) |
|---|
| Disable lock down mode. Enable the ESXi Shell. Login as root and execute the following command(s): # vi /etc/ssh/sshd_config Add/modify the "PermitTunnel" keyword to "no", i.e.; PermitTunnel= no Re-enable lock down mode. |