ESXI-80-000217 The ESXi host must configure virtual switch security policies to reject Media Access Control (MAC) address changes.

Information

If the virtual machine (VM) 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, which will affect applications that require this functionality. This will also affect how a layer 2 bridge will operate and will affect applications that require a specific MAC address for licensing. "Reject MAC Changes" can be set at the vSwitch and/or the Portgroup level. Switch-level settings can be overridden at the Portgroup level.

Solution

From the vSphere Client, go to Hosts and Clusters.

Select the ESXi Host >> Configure >> Networking >> Virtual Switches.

On each standard switch, click "Edit" and select Security.

Set "MAC Address Changes" to "Reject". Click "OK".

For each port group, click the '...' button and select "Edit Settings" then Security.

Set "MAC Address Changes" to "Reject" and uncheck the "Override" box. Click "OK".

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

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_VMW_vSphere_8-0_Y24M08_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|I, CCI|CCI-000366, Rule-ID|SV-258772r959010_rule, STIG-ID|ESXI-80-000217, Vuln-ID|V-258772

Plugin: VMware

Control ID: cf1bbe710ac229bdd8068d69c24f1e7e71f86401068448de116fdab68216cc28