The Aviat WTM must have all user-facing or untrusted ports configured as access switch ports.

Double encapsulation can be initiated by an attacker who has access to a switch port belonging to the native VLAN of the trunk port. Knowing the victim's MAC address and with the victim attached to a different switch belonging to the same trunk group, thereby requiring the trunk link and frame tagging, the malicious user can begin the attack by sending frames with two sets of tags. The outer tag that will have the attacker's VLAN ID (probably the well-known and omnipresent default VLAN) is stripped off by the switch, and the inner tag that will have the victim's VLAN ID is used by the switch as the next hop and sent out the trunk port.

Verify the Aviat WTM has all user-facing or untrusted ports configured as access switch ports with the following steps:

1. Log on to the Web UI using an admin account. 2. Using the Web UI, navigate to Switching and Routing >> VLAN Management >> Membership. 3. For each user-facing or untrusted port, verify the Mode is set to access.

If any user-facing or untrusted port is configured as a trunk, this is a finding.

Configure the Aviat WTM to set all user-facing or untrusted ports as access switch ports with the following steps:

1. Log on to the Web UI using an admin account. 2. Using the Web UI, navigate to Switching and Routing >> VLAN Management >> Membership. 3. For each user-facing or untrusted port configured as a trunk, change the Mode to access. 4. Click "Commit".