The ESXi host must restrict the use of Virtual Guest Tagging (VGT) on standard switches.
An XCCDF Rule
Description
<VulnDiscussion>When a port group is set to VLAN 4095, the vSwitch passes all network frames to the attached virtual machines (VMs) without modifying the VLAN tags. In vSphere, this is referred to as VGT. The VM must process the VLAN information itself via an 802.1Q driver in the operating system. VLAN 4095 must only be implemented if the attached VMs have been specifically authorized and are capable of managing VLAN tags themselves. If VLAN 4095 is enabled inappropriately, it may cause denial of service or allow a VM to interact with traffic on an unauthorized VLAN.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-258775r933386_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
From the vSphere Client, go to Hosts and Clusters.
Select the ESXi Host >> Configure >> Networking >> Virtual Switches.
For each port group on a standard switch that is configured to a native VLAN, click the '...' button next to the port group.