STIGUI
V-286559CAT III — Low severitySV-286559r1274097_rule

The Aviat WTM must not have any switch ports assigned to the native VLAN.

Rule version AWTM-L2-000013 · STIG v1 · 2026-09-15

Discussion

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.

Check

Verify the Aviat WTM does not have any switch ports assigned to the native VLAN 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 switch port, verify the VLAN assignment is not set to the native VLAN ID.

If any switch port is assigned to the native VLAN, this is a finding.

Fix

Configure the Aviat WTM to reassign all switch ports away from the native VLAN 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 switch port assigned to the native VLAN, change the VLAN assignment to a nonnative VLAN. 4. Click "Commit".

Identifiers

Group ID
V-286559
Group title
SRG-NET-000512-L2S-000013
Rule ID
SV-286559r1274097_rule
Check ID
C-91241r1273956_chk
Fix ID
F-91146r1273957_fix