Ensure 'Enumeration policy for external devices incompatible with Kernel DMA Protection' is set to 'Enabled: Block All'


This policy is intended to provide additional security against external DMA-capable devices. It allows for more control over the enumeration of external DMA-capable devices that are not compatible with DMA Remapping/device memory isolation and sandboxing.

The recommended state for this setting is: Enabled: Block All.

Note: This policy does not apply to 1394, PCMCIA or ExpressCard devices. The protection also only applies to Windows 10 R1803 or higher, and also requires a UEFI BIOS to function.

Note #2: More information on this feature is available at this link: Kernel DMA Protection for Thunderbolt(TM) 3 (Windows 10) | Microsoft Docs.


Device memory sandboxing allows the OS to leverage the I/O Memory Management Unit (IOMMU) of a device to block unpermitted I/O, or memory access, by the peripheral.


External devices that are not compatible with DMA-remapping will not be enumerated and will not function unless/until the user has logged in successfully and has an unlocked user session. Once enumerated, these devices will continue to function, regardless of the state of the session. Devices that are compatible with DMA-remapping will be enumerated immediately, with their device memory isolated.


To establish the recommended configuration via GP, set the following UI path to Enabled: Block All:

Computer Configuration\Policies\Administrative Templates\System\Kernel DMA Protection\Enumeration policy for external devices incompatible with Kernel DMA Protection

Note: This Group Policy path may not exist by default. It is provided by the Group Policy template DmaGuard.admx/adml that is included with the Microsoft Windows 10 Release 1809 & Server 2019 Administrative Templates (or newer).

Default Value:

Windows 10 R1803 and newer: Enabled if UEFI BIOS is present. Disabled if using legacy BIOS.

Older OSes: Not supported (i.e. Disabled).

See Also


Item Details


References: 800-53|CM-8, CSCv7|1.4

Plugin: Windows

Control ID: 23713c0acbe56837bd376248d687c90374f35be155773627ec14defc589aeb9b