18.9.78.3 Ensure 'Allow data persistence for Windows Defender Application Guard' is set to 'Disabled'

Information

This policy setting allows you to decide whether data should persist across different sessions in Windows Defender Application Guard (WDAG).

The recommended state for this setting is: Disabled.

Note: WDAG requires a 64-bit version of Windows and a CPU supporting hardware-assisted CPU virtualization (Intel VT-x or AMD-V). This feature is not officially supported on virtual hardware, although it can work on VMs (especially for testing) provided that the hardware-assisted CPU virtualization feature is exposed by the host to the guest VM.

More information on system requirements for this feature can be found at this link:

System requirements for Windows Defender Application Guard (Windows 10) | Microsoft Docs

Rationale:

The primary purpose of Windows Defender Application Guard (WDAG) is to present a 'sandboxed container' for visiting untrusted websites. If data persistence is allowed, then it reduces the effectiveness of the sandboxing, and malicious content will be able to remain active in the WDAG container between sessions.

Solution

To establish the recommended configuration via GP, set the following UI path to Disabled:

Computer Configuration\Policies\Administrative Templates\Windows Components\Windows Defender Application Guard\Allow data persistence for Windows Defender Application Guard

Note: This Group Policy path may not exist by default. It is provided by the Group Policy template AppHVSI.admx/adml that is included with the Microsoft Windows 10 Release 1709 Administrative Templates (or newer).

Impact:

None - this is the default behavior.

Default Value:

Disabled. (Windows Defender Application Guard (WDAG) deletes all user data within the WDAG container.)

See Also

https://workbench.cisecurity.org/files/2550