Information
This policy setting determines whether to save downloaded files to the host operating system from the Windows Defender Application Guard container.
The recommended state for this setting is: Disabled.
Note: Windows Defender Application Guard 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 Application Guard is to present a 'sandboxed container'. Potentially malicious files should not be copied to the host OS from the sandboxed environment, which could put the host at risk.
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 files to download and save to the host operating system from 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 1803 Administrative Templates (or newer).
Impact:
None - this is the default behavior.
Default Value:
Disabled. (People can't save downloaded files from the Windows Defender Application Guard container to the host operating system.)
CIS Controls:
Version 7
13 Data Protection
Data Protection