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18.8.5.5 Ensure 'Turn On Virtualization Based Security: Credential Guard Configuration' is set to 'Enabled with UEFI lock' (MS Only) - Enabled with UEFI lock

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Information

This setting lets users turn on Credential Guard with virtualization-based security to help protect credentials. The 'Enabled with UEFI lock' option ensures that Credential Guard cannot be disabled remotely. In order to disable the feature, you must set the Group Policy to 'Disabled' as well as remove the security functionality from each computer, with a physically present user, in order to clear configuration persisted in UEFI.

The recommended state for this setting is: Enabled with UEFI lock, but only on Member Servers (not Domain Controllers).

Note: Virtualization Based Security requires a 64-bit version of Windows with Secure Boot enabled, which in turn requires that Windows was installed with a UEFI BIOS configuration, not a Legacy BIOS configuration. In addition, if running Windows on a virtual machine, the hardware-assisted CPU virtualization feature (Intel VT-x or AMD-V) must be exposed by the host to the guest VM.

More information on system requirements for this feature can be found at Windows Defender Credential Guard Requirements (Windows 10) | Microsoft Docs

Note #2: Credential Guard and Device Guard are not currently supported when using Azure IaaS VMs.

Rationale:

The Enabled with UEFI lock option ensures that Credential Guard cannot be disabled remotely.




Impact:

Warning: All drivers on the system must be compatible with this feature or the system may crash. Ensure that this policy setting is only deployed to computers which are known to be compatible.

Warning #2: Enabling Windows Defender Credential Guard on Domain Controllers is not supported. The domain controller hosts authentication services which integrate with processes isolated when Windows Defender Credential Guard is enabled, causing crashes.

Warning #3: Once this setting is turned on and active, Credential Guard cannot be disabled solely via GPO or any other remote method. After removing the setting from GPO, the features must also be manually disabled locally at the machine using the steps provided at this link:

Manage Windows Defender Credential Guard (Windows 10) | Microsoft Docs

Solution

To establish the recommended configuration via GP, set the following UI path to Enabled with UEFI lock (on Member Servers only):

Computer Configuration\Policies\Administrative Templates\System\Device Guard\Turn On Virtualization Based Security: Credential Guard Configuration

Note: This Group Policy path may not exist by default. It is provided by the Group Policy template DeviceGuard.admx/adml that is included with the Microsoft Windows 10 Release 1511 Administrative Templates (or newer).

Default Value:

Disabled.

See Also

https://workbench.cisecurity.org/files/3458

Item Details

References: CSCv6|16.14, CSCv7|16.4

Plugin: Windows

Control ID: eaf520ecf91ba9dcfcb17123063dc4c6aa2d4e3b2658669cd48e27a7cd1488f6