ESXI5-VMNET-000016 - The system must ensure the virtual switches MAC Address Change policy is set to reject

Information

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. An example of an application like this is Microsoft Clustering, which requires systems to effectively share a MAC address. This will also affect how a layer 2 bridge will operate. This will also affect applications that require a specific MAC address for licensing. An exception should be made for the dvPortgroups that these applications are connected to.

Solution

From the vSphere Client, connect to the vCenter Server and as administrator: Go to 'Home>> Inventory>> Hosts and clusters'. Select each ESXi host with active virtual switches connected to active VMs requiring securing. Go to tab 'Configuration>> Network>> vSwitch(?)>> Properties>> Ports>> vSwitch>> Default Policies>> Security'. Change the 'Mac Address Changes' = 'Reject'.

See Also

http://iasecontent.disa.mil/stigs/zip/U_ESXi5_Server_V1R10_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7, CAT|I, CCI|CCI-000366, CSCv6|9.2, Group-ID|V-39373, Rule-ID|SV-51231r1_rule, STIG-ID|ESXI5-VMNET-000016, Vuln-ID|V-39373

Plugin: VMware

Control ID: 910e4a479b74df149b6f7d07c41663b688c1f0eed5938267593654f943766ba0