18.9.5.2 (NG) Ensure 'Turn On Virtualization Based Security: Select Platform Security Level' is set to 'Secure Boot' or higher

Information

This policy setting specifies whether Virtualization Based Security (VBS) is enabled. VBS uses the Windows Hypervisor to provide support for security services.

The recommended state for this setting is: Secure Boot or Secure Boot and DMA Protection

Note: VBS 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.

Secure Boot can help reduce the risk of bootloader attacks and in conjunction with DMA protections to help protect data from being scraped from memory.

Solution

To establish the recommended configuration via GP, set the following UI path to Secure Boot or Secure Boot and DMA Protection :

Computer Configuration\Policies\Administrative Templates\System\Device Guard\Turn On Virtualization Based Security: Select Platform Security Level

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 RTM (Release 1507) Administrative Templates (or newer).

Impact:

Choosing the Secure Boot option provides the system with as much protection as is supported by the computer's hardware. A system with input/output memory management units (IOMMUs) will have Secure Boot with DMA protection. A system without IOMMUs will simply have Secure Boot enabled without DMA protection.

Choosing the Secure Boot with DMA protection option requires the system to have IOMMUs in order to enable VBS. Without IOMMU hardware support, VBS will be disabled.

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.

See Also

https://workbench.cisecurity.org/benchmarks/16912