Identity Service, Microsoft 365 Experts
From Microsoft Corporation
Technical Bulletin MC468492 · Published Nov 18, 2022
Microsoft Authenticator App’s number matching is Generally Available! Microsoft will start enabling this critical security feature for all users of the Microsoft Authenticator app.
When this will happen:
Beginning February 27, 2023
How this affects your organization:
To prevent accidental approvals, admins can require users to enter a number displayed on the sign-in screen when approving an MFA request in the Microsoft Authenticator app. This feature is critical to protecting against MFA fatigue attacks which are on the rise.
Another way to reduce accidental approvals is to show users additional context in Authenticator notifications. Admins can now selectively choose to enable the following:
- Application context: Show users which application they are signing into.
- Geographic location context: Show users their sign-in location based on the IP address of the device they are signing into.
Number match behavior in different scenarios after 27-February 2023:
- Authentication flows will require users to do number match when using the Microsoft Authenticator app. If the user is using a version of the Authenticator app that doesn’t support number match, their authentication will fail. Please make sure upgrade to the latest version of Microsoft Authenticator (App Store and Google Play Store) to use it for sign-in.
- Self Service Password Reset (SSPR) and combined registration flows will also require number match when users are using the Microsoft Authenticator app.
- ADFS adapter will require number matching on versions of Windows Server that support number matching. On earlier versions, users will continue to see the “Approve/Deny” experience and won’t see number matching till you upgrade.
- NPS extension versions beginning 1.2.2131.2 will require users to do number matching after 27-February 2023. Because the NPS extension can’t show a number, the user will be asked to enter a One-Time Passcode (OTP). The user must have an OTP authentication method (e.g. Microsoft Authenticator app, software tokens etc.) registered to see this behavior. If the user doesn’t have an OTP method registered, they’ll continue to get the Approve/Deny experience. You can create a registry key that overrides this behavior and prompts users with Approve/Deny. More information can be found in the number matching documentation.
- Apple Watch – Apple Watch will remain unsupported for number matching. We recommend you uninstall the Microsoft Authenticator Apple Watch app because you have to approve notifications on your phone.
What you can do to prepare:
We highly recommend that you leverage the rollout controls (via Azure Portal Admin UX and MSGraph APIs) to smoothly deploy these features (number match and additional context) for users of the Microsoft Authenticator app.
Learn more at:
- Number match documentation
- Defend your users from MFA fatigue attacks – Microsoft Community Hub
- Advanced Microsoft Authenticator security features are now generally available! – Microsoft Community Hub