Application Guard for Office (public preview) for admins

Applies to: Word, Excel, and PowerPoint for Microsoft 365, Windows 10 Enterprise

Important

Some information relates to a prereleased product which may be substantially modified before it's commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Microsoft Defender Application Guard for Office (Application Guard for Office) helps prevent untrusted files from accessing trusted resources, keeping your enterprise safe from new and emerging attacks. This article walks admins through setting up devices for a preview of Application Guard for Office. It provides information about system requirements and installation steps to enable Application Guard for Office on a device.

Prerequisites

Minimum hardware requirements

  • CPU: 64-bit, 4 cores (physical or virtual), virtualization extensions (Intel VT-x OR AMD-V), Core i5 equivalent or higher recommended
  • Physical memory: 8-GB RAM
  • Hard disk: 10 GB of free space on the system drive (SSD recommended)

Minimum software requirements

  • Windows 10: Windows 10 Enterprise edition, Client Build version 2004 (20H1) build 19041
  • Office: Office Beta Channel Build version 2008 16.0.13212 or later
  • Update package: Windows 10 cumulative monthly security updates KB4571756

For detailed system requirements, refer to System requirements for Microsoft Defender Application Guard. To learn more about Office Insider Preview builds, refer to Getting started on deploying Office Insider builds.

Licensing requirements

  • Microsoft 365 E5 or Microsoft 365 E5 Security

Deploy Application Guard for Office

Enable Application Guard for Office

  1. Download and install Windows 10 cumulative monthly security updates KB4571756.

  2. Select Microsoft Defender Application Guard under Windows Features and select OK. Enabling the Application Guard feature will prompt a system reboot. You can choose to reboot now or after step 3.

    Windows Features dialog box showing AG

    The feature can also be enabled by running the following PowerShell command as administrator:

    Enable-WindowsOptionalFeature -online -FeatureName Windows-Defender-ApplicationGuard 
    
  3. Look for the Microsoft Defender Application Guard in Managed Mode group policy located at Computer Configuration\Administrative Templates\Windows Components\Microsoft Defender Application Guard. Turn this policy on by setting the value under Options as 2 or 3 then selecting OK or Apply.

    Turn on AG in Managed Mode

    Alternatively, you can set the corresponding CSP policy:

    OMA-URI: ./Device/Vendor/MSFT/WindowsDefenderApplicationGuard/Settings/AllowWindowsDefenderApplicationGuard
    Data type: Integer
    Value: 2

  4. Reboot the system.

Set Diagnostics & feedback to send full data

This step ensures that the data necessary to identify and fix problems is reaching Microsoft. Follow these steps to enable diagnostics on your Windows device:

  1. Open Settings from the Start menu.

    Start menu

  2. On Windows Settings, select Privacy.

    Windows Settings menu

  3. Under Privacy, select Diagnostics & feedback and select Optional diagnostic data.

    Diagnostics and feedback menu

For more on configuring Windows diagnostic settings, refer to Configuring Windows diagnostic data in your organization.

Confirm that Application Guard for Office is enabled and working

Before confirming that the Application Guard for Office is enabled, launch Word, Excel, or PowerPoint on a device where the policies have been deployed. Make sure Office is activated. You may need to use your work identity to activate the Office product first.

To confirm that Application Guard for Office is now enabled, launch Word, Excel, or PowerPoint and open an untrusted document. For example, you can open a document downloaded from the internet or an email attachment from someone outside your organization.

On the first launch of an untrusted file, you may see an Office splash screen like the one below. It might show for some time while Application Guard for Office is being activated and the file is being opened. Subsequent launches of untrusted files should be faster.

Office app splash screen

Upon being opened, the file should display a few visual indicators that the file was opened inside Application Guard for Office:

  • A callout in the ribbon

    Doc file showing small App Guard note

  • The application icon with a shield in the taskbar

    Icon in taskbar

Configure Application Guard for Office

Office supports the following policies to enable you to configure the capabilities of Application Guard for Office. These policies can be configured through Group policies or through the Office cloud policy service.

Note

These policies will become available soon. Also, configuring these policies can disable some functionalities for files opened in Application Guard for Office.

Policy Description
Disable Application Guard for Office Enabling this policy will force Word, Excel, and PowerPoint to use the Protected View isolation container instead of Application Guard for Office. This policy can be used to temporarily disable Application Guard for Office when there are issues in leaving it enabled for Edge.
Disable copy/paste for documents opened in Application Guard Enabling this policy will prevent a user from copying and pasting content from a document opened in Application Guard for Office to a document opened outside it.
Prevent users from removing Application Guard protection on files Enabling this policy will remove the option (within the Office application experience) to disable Application Guard protection or open a file outside Application Guard.

Note: Users can still bypass this policy by manually removing the mark-of-the-web property from the file or by moving a document to a Trusted location.
Restrict printing from documents opened in Application Guard Enabling this policy will limit printers a user can print to from a file opened in Application Guard for Office. For example, you can use this policy to restrict users to only print to PDF.
Turn off camera and microphone access for documents opened in Application Guard Enabling this policy will remove Office access to Camera and Microphone inside Application Guard for Office.

Note

The following policies will require the user to log off and re-login to Windows to take effect:

  • Disable copy/paste for documents opened in Application Guard
  • Restrict printing for documents opened in Application Guard
  • Turn off camera and mic access to documents opened in Application Guard

Submit feedback

Submit feedback via Feedback Hub

If you encounter any issues when launching Application Guard for Office, you are encouraged to submit your feedback via Feedback Hub:

  1. Open the Feedback Hub app and sign in.

  2. If you get an error dialog while launching Application Guard, select Report to Microsoft in the error dialog to start a new feedback submission. Otherwise, navigate to https://aka.ms/wdagoffice-fb to select the correct category for Application Guard, then select + Add new feedback near the top right.

  3. Fill in the Summarize your feedback box if it isn’t already filled in for you.

  4. Fill in the Explain in more detail box with a detailed description of the issue you experienced and what steps you took, then select Next.

  5. Select the bubble next to Problem. Make sure the category selected is Security and Privacy > Microsoft Defender Application Guard – Office, then select Next.

  6. Select New feedback, then Next.

  7. Collect traces about the issue:

    1. Expand the Recreate my problem tile.

    2. If the issue you’re experiencing occurs while Application Guard is running, open an Application Guard instance. Doing this allows additional traces to be collected from within the Application Guard container.

    3. Select Start recording and wait for the tile to stop spinning and say Stop recording.

    4. Fully reproduce the issue with Application Guard. This might include attempting to launch an Application Guard instance and waiting until it fails, or reproducing an issue in a running Application Guard instance.

    5. Select the Stop recording tile.

    6. Keep any running Application Guard instance/s open, even until a few minutes after submission, so that container diagnostics can also be collected.

  8. Attach any relevant screenshots or files related to the problem.

  9. Select Submit.

Submit feedback via Office Customer Voice

You may also submit feedback from within Office if the issue happens when Office documents are opened in Application Guard. Refer to the Office Insider Handbook for submitting feedback.

Integration with Microsoft Defender ATP and Office ATP

Application Guard for Office is integrated with Microsoft Defender Advance Threat Protection (ATP) to provide monitoring and alerting on malicious activity happening in the isolated environment.

Microsoft Defender ATP is a security platform designed to help enterprise networks prevent, detect, investigate, and respond to advanced threats. For more details about this platform, visit the Microsoft Defender Advanced Threat Protection page. Learn more about onboarding devices to this platform at Onboard devices to the Microsoft Defender ATP service.

You can also configure Office 365 ATP to work with Microsoft Defender ATP. Refer to Integrate Office 365 ATP with Microsoft Defender ATP.

Limitations and considerations

  • Application Guard for Office is a restricted mode that isolates untrusted documents from accessing trusted corporate resources, intranet, the user's identity, and arbitrary files present on the computer. As a result, if a user tries to access a feature that has a dependency on such access, for example, inserting a picture from a local file on disk, it will fail and produce a prompt like the one below. To enable an untrusted document to access trusted resources, users must remove Application Guard protection from the document.

    Dialog box saying To help you keep safe, this feature is not available

    Note

    Advise users to only remove protection if they trust the file and its source or where it came from.

  • Active content in documents like macros and ActiveX controls are disabled in Application Guard for Office. Users need to remove Application Guard protection to enable active content.

  • Untrusted files opened from network shares or files shared from OneDrive, OneDrive for Business, or SharePoint Online from a different organization open as read-only in Application Guard. Users can save a local copy of such files to continue working in the container or remove protection to directly work with the original file.

  • Files that are protected by Information Rights Management (IRM) continue to open in Protected View.

  • Any customizations to Office applications in Application Guard for Office will not persist after a user logs off and logs back in or reboots the device.

  • Only Accessibility tools that use the UIA framework can provide an accessible experience for files opened in Application Guard for Office.

  • Network connectivity is required for the first launch of Application Guard after installation. This is required for Application Guard to validate the license.

  • In the document's info section, the Last Modified By property may display WDAGUtilityAccount as the user. This is the anonymous user configured in Application Guard given that the desktop user's identity is not shared inside the Application Guard container.

Performance optimizations for Application Guard

This section provides an overview of the performance optimizations used in Application Guard for Office. This information can help administrators diagnose reports from users related to the performance of Office or the overall system when Application Guard is enabled.

Application Guard uses a virtualized container to isolate untrusted documents away from the system. The process of creating a container and setting up the Application Guard container to open Office documents has a performance overhead that might negatively impact user experience when users open an untrusted document.

To provide users with the expected file opening experience, Application Guard uses logic to pre-create a container when the following heuristic is met on a system: A user has opened a file in either Protected View or Application Guard in the past 28 days.

When this heuristic is met, Office will pre-create an Application Guard container for the user after they log in to Windows. When this pre-create operation is in progress, the system may experience slow performance. This will resolve as soon as the operation completes.

Note

The hints needed for the heuristic used to pre-create the container are generated by Office applications as a user uses them. If a user installs Office on a new system where Application Guard is enabled, Office will not pre-create the container until after the first time a user opens an untrusted document on the system. The user will observe that this first file takes longer to open in Application Guard.

Known issues in preview