The NSX Tier-0 Gateway router must be configured to have all inactive interfaces removed.

An inactive interface is rarely monitored or controlled and may expose a network to an undetected attack on that interface. Unauthorized personnel with access to the communication facility could gain access to a router by connecting to a configured interface that is not in use.

If an interface is no longer used, the configuration must be deleted and the interface disabled. For sub-interfaces, delete sub-interfaces that are on inactive interfaces and delete sub-interfaces that are themselves inactive. If the sub-interface is no longer necessary for authorized communications, it must be deleted.

From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways.

For every Tier-0 Gateway, expand the Tier-0 Gateway >> Interfaces and GRE Tunnels, and click on the number of interfaces present to open the interfaces dialog.

Review each interface present to determine if they are not in use or inactive.

If there are any interfaces present on a Tier-0 Gateway that are not in use or inactive, this is a finding.

Remove unused interfaces by doing the following:

From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways and expand the target Tier-0 gateway.

Expand "Interfaces and GRE Tunnels", then click on the number of interfaces present to open the interfaces dialog.

Select "Delete" on the unneeded interface, and then click "Delete" again to confirm.