I need to locate a telephone number inside my user database in the multifacor authentication section. How can I locate a telephone number when I do not know the user assigned to it?

Hello @Joe Reynolds

You can locate the user associated with a specific phone number in the Microsoft Entra admin center by following these steps:
Go to https://entra.microsoft.com and sign in with the appropriate admin credentials.

In the left-hand navigation, select Microsoft Entra ID > Users.

Use the Add filters option at the top.

Select Mobile phone as the filter, set the operator to Starts with, and enter the known digits of the phone number.

This will return a list of users whose mobile number matches the criteria.

To verify further, select a user from the results, go to Authentication methods, and check if the phone number is registered under their methods.

This is helpful when you have a phone number but need to identify the associated user account, especially in cases involving MFA.

To retrieve all user authentication methods using Microsoft Graph Explorer, you can query the Authentication Methods API. Here's how you can do it:

If you know the user id you can check with Graph Explorer by following the below

Steps:

Open Microsoft Graph Explorer.

Sign in with your Microsoft account to access the data.

Use the following HTTP GET request to retrieve all authentication methods for a specific user:

GET https://graph.microsoft.com/v1.0/users/{user-id}/authentication

Replace {user-id} with the actual user ID or email address.

Example Response:

The response will include details about the user's authentication methods, such as password, FIDO2 security keys, Microsoft Authenticator, phone methods, etc.

{

Notes:

• Ensure you have the necessary permissions, such as UserAuthenticationMethod.Read.All or User.Read.All, in your Azure AD app registration.
• If you're testing in Graph Explorer, you may need to consent to the required permissions. To retrieve all user authentication methods using Microsoft Graph Explorer, you can query the Authentication Methods API.

Hope this helps.

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