Details

If the virtual machine operating system changes the MAC address, it can send frames with an impersonated source MAC address at any time. This allows it to stage malicious attacks on the devices in a network by impersonating a network adaptor authorized by the receiving network. This will prevent VMs from changing their effective MAC address. It will affect applications that require this functionality. This will also affect how a layer 2 bridge will operate. This will also affect applications that require a specific MAC address for licensing.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

From the vSphere Web Client go to Networking >> Select a distributed switch >> Select a port group >> Configure >> Settings >> Policies >> Edit >> Security. Set ‘MAC Address Changes’ to reject. Click ‘OK’.

or

From a PowerCLI command prompt while connected to the vCenter server run the following commands:
Get-VDSwitch | Get-VDSecurityPolicy | Set-VDSecurityPolicy -MacChanges $false
Get-VDPortgroup | ?{$_.IsUplink -eq $false} | Get-VDSecurityPolicy | Set-VDSecurityPolicy -MacChanges $false

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_VMW_vSphere_6-5_Y21M10_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system VMware.

References

• 800-53|CM-6b.
• CAT|I
• CCI|CCI-000366
• Rule-ID|SV-216836r612237_rule
• STIG-ID|VCWN-65-000014
• STIG-Legacy|SV-104569
• STIG-Legacy|V-94739
• Vuln-ID|V-216836

Source

• Tenable.com/audits