The Arista MLS layer 2 switch must not have any switch ports assigned to the native VLAN.
An XCCDF Rule
Description
<VulnDiscussion>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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-255986r991780_rule
- Severity
- Low
- References
- Updated
Remediation - Manual Procedure
Configure the Arista MLS switch to ensure all access switch ports use a VLAN other than the native VLAN.
Configure all access switch ports to a VLAN other than the designated native VLAN by using the following example:
switch(config)#interface Ethernet 21
switch(config-Eth21)# switchport access vlan xxxx