Enforce Microsoft Entra multifactor authentication for Azure Virtual Desktop using Conditional Access

Users can sign into Azure Virtual Desktop from anywhere using different devices and clients. However, there are certain measures you should take to help keep your environment and your users safe. Using Microsoft Entra multifactor authentication (MFA) with Azure Virtual Desktop prompts users during the sign-in process for another form of identification in addition to their username and password. You can enforce MFA for Azure Virtual Desktop using Conditional Access, and can also configure whether it applies to the web client, mobile apps, desktop clients, or all clients.

When a user connects to a remote session, they need to authenticate to the Azure Virtual Desktop service and the session host. If MFA is enabled, it's used when connecting to the Azure Virtual Desktop service and the user is prompted for their user account and a second form of authentication, in the same way as accessing other services. When a user starts a remote session, a username and password is required for the session host, but this is seamless to the user if single sign-on (SSO) is enabled. For more information, see Authentication methods.

How often a user is prompted to reauthenticate depends on Microsoft Entra session lifetime configuration settings. For example, if their Windows client device is registered with Microsoft Entra ID, it receives a Primary Refresh Token (PRT) to use for single sign-on (SSO) across applications. Once issued, a PRT is valid for 14 days and is continuously renewed as long as the user actively uses the device.

While remembering credentials is convenient, it can also make deployments for Enterprise scenarios using personal devices less secure. To protect your users, you can make sure the client keeps asking for Microsoft Entra multifactor authentication credentials more frequently. You can use Conditional Access to configure this behavior.

Learn how to enforce MFA for Azure Virtual Desktop and optionally configure sign-in frequency in the following sections.

Prerequisites

Here's what you need to get started:

• Assign users a license that includes Microsoft Entra ID P1 or P2.
• A Microsoft Entra group with your Azure Virtual Desktop users assigned as group members.
• Enable Microsoft Entra multifactor authentication.

Create a Conditional Access policy

Here's how to create a Conditional Access policy that requires multifactor authentication when connecting to Azure Virtual Desktop:

1. Sign in to the Microsoft Entra admin center as at least a Conditional Access Administrator.

2. Browse to Protection > Conditional Access > Policies.

3. Select New policy.

4. Give your policy a name. We recommend that organizations create a meaningful standard for the names of their policies.

5. Under Assignments > Users, select 0 users and groups selected.

6. Under the Include tab, select Select users and groups and check Users and groups, then under Select, select 0 users and groups selected.

7. On the new pane that opens, search for and choose the group that contains your Azure Virtual Desktop users as group members, then select Select.

8. Under Assignments > Target resources, select No target resources selected.

9. Under the Include tab, select Select apps, then under Select, select None.

10. On the new pane that opens, search for and select the necessary apps based on the resources you're trying to protect. When searching for an application name on Azure, use search terms that begin with the application name in order instead of keywords the application name contains out of order. For example, when you want to use Azure Virtual Desktop, you need to enter 'Azure Virtual', in that order. If you enter 'virtual' by itself, the search doesn't return the desired application.

    • Azure Virtual Desktop

    For Azure Virtual Desktop (based on Azure Resource Manager), you can configure MFA on these different apps:

    • Azure Virtual Desktop (app ID 9cdead84-a844-4324-93f2-b2e6bb768d07), which applies when the user subscribes to Azure Virtual Desktop, authenticates to the Azure Virtual Desktop Gateway during a connection, and when diagnostics information is sent to the service from the user's local device.

      Tip

      The app name was previously Windows Virtual Desktop. If you registered the Microsoft.DesktopVirtualization resource provider before the display name changed, the application will be named Windows Virtual Desktop with the same app ID as Azure Virtual Desktop.

      • Microsoft Remote Desktop (app ID a4a365df-50f1-4397-bc59-1a1564b8bb9c) and Windows Cloud Login (app ID 270efc09-cd0d-444b-a71f-39af4910ec45). These apply when the user authenticates to the session host when single sign-on is enabled. It's recommended to match conditional access policies between these apps and the Azure Virtual Desktop app, except for the sign-in frequency.

      Important

      The clients used to access Azure Virtual Desktop use the Microsoft Remote Desktop Entra ID app to authenticate to the session host today. An upcoming change will transition the authentication to the Windows Cloud Login Entra ID app. To ensure a smooth transition, you need to add both Entra ID apps to your CA policies.

    Important

    Don't select the app called Azure Virtual Desktop Azure Resource Manager Provider (app ID 50e95039-b200-4007-bc97-8d5790743a63). This app is only used for retrieving the user feed and shouldn't have multifactor authentication.

11. Once you selected your apps, select Select.

    

12. Under Assignments > Conditions, select 0 conditions select.

13. Under Client apps, select Not configured.

14. On the new pane that opens, for Configure, select Yes.

15. Select the client apps this policy applies to:

    • Select Browser if you want the policy to apply to the web client.
    • Select Mobile apps and desktop clients if you want to apply the policy to other clients.
    • Select both check boxes if you want to apply the policy to all clients.
    • Deselect values for legacy authentication clients.

    

16. Once you selected the client apps this policy applies to, select Done.

17. Under Access controls > Grant, select 0 controls selected.

18. On the new pane that opens, select Grant access.

19. Check Require multifactor authentication, and then select Select.

20. At the bottom of the page, set Enable policy to On and select Create.

Configure sign-in frequency

Sign-in frequency policies let you configure how often users are required to sign-in when accessing Microsoft Entra-based resources. This can help secure your environment and is especially important for personal devices, where the local OS may not require MFA or may not lock automatically after inactivity. Users are prompted to authenticate only when a new access token is requested from Microsoft Entra ID when accessing a resource.

Sign-in frequency policies result in different behavior based on the Microsoft Entra app selected:

To configure the time period after which a user is asked to sign-in again:

1. Open the policy you created previously.
2. Under Access controls > Session, select 0 controls selected.
3. In the Session pane, select Sign-in frequency.
4. Select Periodic reauthentication or Every time.
   • If you select Periodic reauthentication, set the value for the time period after which a user is asked to sign-in again when performing an action that requires a new access token, and then select Select. For example, setting the value to 1 and the unit to Hours, requires multifactor authentication if a connection is launched more than an hour after the last user authentication.
   • The Every time option is currently available in preview and is only supported when applied to the Microsoft Remote Desktop and Windows Cloud Login apps when single sign-on is enabled for your host pool. If you select Every time, users are prompted to reauthenticate when launching a new connection after a period of 5 to 10 minutes since their last authentication.
5. At the bottom of the page, select Save.

Microsoft Entra joined session host VMs

For connections to succeed, you must disable the legacy per-user multifactor authentication sign-in method. If you don't want to restrict signing in to strong authentication methods like Windows Hello for Business, you need to exclude the Azure Windows VM Sign-In app from your Conditional Access policy.

Next steps

• Learn more about Conditional Access policies