Check: VCTR-67-000013
VMware vSphere 6.7 vCenter STIG:
VCTR-67-000013
(in versions v1 r4 through v1 r2)
Title
The vCenter Server must set the distributed port group Forged Transmits policy to reject. (Cat II impact)
Discussion
If the virtual machine operating system changes the MAC address, the operating system can send frames with an impersonated source MAC address at any time. This allows an operating system to stage malicious attacks on the devices in a network by impersonating a network adaptor authorized by the receiving network. When the Forged transmits option is set to "Accept", ESXi does not compare source and effective MAC addresses. To protect against MAC impersonation, set the Forged transmits option to "Reject". The host will compare the source MAC address being transmitted by the guest operating system with the effective MAC address for its virtual machine adapter to determine if they match. If the addresses do not match, the ESXi host drops the packet.
Check Content
If distributed switches are not used, this is not applicable. From the vSphere Client, go to Networking >> select a distributed switch >> select a port group >> Configure >> Settings >> Policies. Verify "Forged Transmits" is set to reject. or From a PowerCLI command prompt while connected to the vCenter server, run the following commands: Get-VDSwitch | Get-VDSecurityPolicy Get-VDPortgroup | ?{$_.IsUplink -eq $false} | Get-VDSecurityPolicy If the "Forged Transmits" policy is set to accept for a non-uplink port, this is a finding.
Fix Text
From the vSphere Client, go to Networking >> select a distributed switch >> select a port group >> Configure >> Settings >> Policies >> Edit >> Security. Set "Forged Transmits" 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 -ForgedTransmits $false Get-VDPortgroup | ?{$_.IsUplink -eq $false} | Get-VDSecurityPolicy | Set-VDSecurityPolicy -ForgedTransmits $false
Additional Identifiers
Rule ID: SV-243082r879887_rule
Vulnerability ID: V-243082
Group Title: SRG-APP-000516
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-000366 |
The organization implements the security configuration settings. |
Controls
Number | Title |
---|---|
CM-6 |
Configuration Settings |