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. Reject MAC Changes can be set at the vSwitch and/or the Portgroup level. You can override switch level settings at the Portgroup level.
Solution
From the vSphere Web Client go to Configure >> Networking >> Virtual Switches. For each virtual switch and port group click Edit settings and change ‘MAC Address Changes’ to reject.
or
From a PowerCLI command prompt while connected to the ESXi host run the following commands:
Get-VirtualSwitch | Get-SecurityPolicy | Set-SecurityPolicy -MacChanges $false
Get-VirtualPortGroup | Get-SecurityPolicy | Set-SecurityPolicy -MacChangesInherited $true
Supportive Information
The following resource is also helpful.
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-207659r388482_rule
- STIG-ID|ESXI-65-000060
- STIG-Legacy|SV-104153
- STIG-Legacy|V-94067
- Vuln-ID|V-207659