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Configure your App Service or Azure Functions app to use Microsoft Entra sign-in

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Note

Starting June 1, 2024, newly created App Service apps can generate a unique default hostname that uses the naming convention <app-name>-<random-hash>.<region>.azurewebsites.net. Existing app names remain unchanged. For example:

myapp-ds27dh7271aah175.westus-01.azurewebsites.net

For more information, see Unique Default Hostname for App Service Resource.

Select another authentication provider to jump to it.

This article shows you how to configure authentication for Azure App Service or Azure Functions so that your app signs in users with the Microsoft identity platform (Microsoft Entra) as the authentication provider.

Choose a tenant for your application and its users

Before your application can sign in users, you need to register it in a workforce or external tenant. If you're making your app available to employee or business guests, register your app in a workforce tenant. If your app is for consumers and business customers, register it in an external tenant.

  1. Sign in to the Azure portal and navigate to your app.

  2. On your app's left menu, select Settings > Authentication, and then select Add identity provider.

  3. In the Add an identity provider page, select Microsoft as the Identity provider to sign in Microsoft and Microsoft Entra identities.

  4. Under Choose a tenant for your application and its users, select Workforce configuration (current tenant) for employees and business guests or select External configuration for consumers and business customers.

Choose the app registration

The App Service Authentication feature can automatically create an app registration for you or you can use a registration that you or a directory admin creates separately.

Create a new app registration automatically, unless you need to create an app registration separately. You can customize the app registration in the Microsoft Entra admin center later if you want.

The following situations are the most common cases to use an existing app registration:

  • Your account doesn't have permissions to create app registrations in your Microsoft Entra tenant.
  • You want to use an app registration from a different Microsoft Entra tenant than the one your app is in.
  • The option to create a new registration isn't available for government clouds.

You can create and use a new app registration (option 1) or use an existing registration created separately (option 2).

Option 1: Create and use a new app registration

Use this option unless you need to create an app registration separately. You can customize the app registration in Microsoft Entra after you create it.

Note

The option to create a new registration automatically isn't available for government clouds. Instead, define a registration separately.

  1. Select Create new app registration.

  2. Enter the Name for the new app registration.

  3. Select the Supported account type:

    • Current tenant - Single tenant. Accounts in this organizational directory only. All user and guest accounts in your directory can use your application or API. Use this option if your target audience is internal to your organization.
    • Any Microsoft Entra directory - Multitenant. Accounts in any organizational directory. All users with a work or school account from Microsoft can use your application or API. These accounts include schools and businesses that use Office 365. Use this option if your target audience is business or educational customers and to enable multitenancy.
    • Any Microsoft Entra directory & personal Microsoft accounts. Accounts in any organizational directory and personal Microsoft accounts (for example, Skype, Xbox). All users with a work or school, or personal Microsoft account can use your application or API. It includes schools and businesses that use Office 365 as well as personal accounts that are used to sign in to services like Xbox and Skype. Use this option to target the widest set of Microsoft identities and to enable multitenancy.
    • Personal Microsoft accounts only. Personal accounts that are used to sign in to services like Xbox and Skype. Use this option to target the widest set of Microsoft identities.

You can change the name of the registration or the supported account types later if you want.

A client secret is created as a slot-sticky application setting named MICROSOFT_PROVIDER_AUTHENTICATION_SECRET. If you want to manage the secret in Azure Key Vault, you can update that setting later to use Key Vault references.

Option 2: Use an existing registration created separately

Select either:

  • Pick an existing app registration in this directory and select an app registration from the dropdown list.

  • Provide the details of an existing app registration and provide:

    • Application (client) ID.
    • Client secret (recommended). A secret value that the application uses to prove its identity when requesting a token. This value is saved in your app's configuration as a slot-sticky application setting named MICROSOFT_PROVIDER_AUTHENTICATION_SECRET. If the client secret isn't set, sign-in operations from the service use the OAuth 2.0 implicit grant flow, which isn't recommended.
    • Issuer URL, which takes the form <authentication-endpoint>/<tenant-id>/v2.0. Replace <authentication-endpoint> with the authentication endpoint value specific to the cloud environment. For example, a workforce tenant in global Azure would use "https://sts.windows.net" as its authentication endpoint.

If you need to manually create an app registration in a workforce tenant, see Register an application with the Microsoft identity platform. As you go through the registration process, be sure to note the application (client) ID and client secret values.

During the registration process, in the Redirect URIs section, select Web for platform and type <app-url>/.auth/login/aad/callback. For example, https://contoso.azurewebsites.net/.auth/login/aad/callback.

After creation, modify the app registration:

  1. From the left navigation, select Expose an API > Add > Save. This value uniquely identifies the application when it's used as a resource, which allows tokens to be requested that grant access. The value is a prefix for scopes you create.

    For a single-tenant app, you can use the default value, which is in the form api://<application-client-id>. You can also specify a more readable URI like https://contoso.com/api based on one of the verified domains for your tenant. For a multitenant app, you must provide a custom URI. For more information about accepted formats for App ID URIs, see Security best practices for application properties in Microsoft Entra ID.

  2. Select Add a scope.

    1. In Scope name, enter user_impersonation.
    2. In Who can consent, select Admins and users if you want to allow users to consent to this scope.
    3. Enter the consent scope name. Enter a description you want users to see on the consent page. For example, enter Access <application-name>.
    4. Select Add scope.

  3. (Recommended) To create a client secret:

    1. From the left navigation, select Certificates & secrets > Client secrets > New client secret.
    2. Enter a description and expiration and select Add.
    3. In the Value field, copy the client secret value. After you navigate away from this page, it doesn't appear again.

  4. (Optional) To add multiple Reply URLs, select Authentication.

Configure additional checks

Additional checks determine which requests are allowed to access your application. You can customize this behavior now or adjust these settings later from the main Authentication screen by choosing Edit next to Authentication settings.

For Client application requirement, choose whether to:

  • Allow requests only from this application itself
  • Allow requests from specific client applications
  • Allow requests from any application (Not recommended)

For Identity requirement, choose whether to:

  • Allow requests from any identity
  • Allow requests from specific identities

For Tenant requirement, choose whether to:

  • Allow requests only from the issuer tenant
  • Allow requests from specific tenants
  • Use default restrictions based on issuer

Your app might still need to make other authorization decisions in code. For more information, see Use a built-in authorization policy.

Configure authentication settings

These options determine how your application responds to unauthenticated requests. The default selections redirect all requests to sign in with this new provider. You can change customize this behavior now or adjust these settings later from the main Authentication screen by choosing Edit next to Authentication settings. For more information, see Authentication flow.

For Restrict access, decide whether to:

  • Require authentication
  • Allow unauthenticated access

For Unauthenticated requests

  • HTTP 302 Found redirect: recommended for websites
  • HTTP 401 Unauthorized: recommended for APIs
  • HTTP 403 Forbidden
  • HTTP 404 Not found

Select Token store (recommended). The token store collects, stores, and refreshes tokens for your application. You can disable this behavior later if your app doesn't need tokens or you need to optimize performance.

Add the identity provider

If you selected workforce configuration, you can select Next: Permissions and add any Microsoft Graph permissions needed by the application. These permissions are added to the app registration, but you can also change them later. If you selected external configuration, you can add Microsoft Graph permissions later.

  • Select Add.

You're now ready to use the Microsoft identity platform for authentication in your app. The provider is listed on the Authentication screen. From there, you can edit or delete this provider configuration.

For an example of configuring Microsoft Entra sign-in for a web app that accesses Azure Storage and Microsoft Graph, see Add app authentication to your web app.

Authorize requests

By default, App Service Authentication only handles authentication. It determines whether the caller is who they say they are. Authorization, determining whether that caller should have access to some resource, is a step beyond authentication. For more information, see Authorization basics.

Your app can make authorization decisions in code. App Service Authentication provides some built-in checks, which can help, but they alone might not be sufficient to cover the authorization needs of your app.

Tip

Multitenant applications should validate the issuer and tenant ID of the request as part of this process to make sure the values are allowed. When App Service Authentication is configured for a multitenant scenario, it doesn't validate which tenant the request comes from. An app might need to be limited to specific tenants, based on if the organization has signed up for the service, for example. See Update your code to handle multiple issuer values.

Perform validations from application code

When you perform authorization checks in your app code, you can use the claims information that App Service Authentication makes available. For more information, see Access user claims in app code.

The injected x-ms-client-principal header contains a Base64-encoded JSON object with the claims asserted about the caller. By default, these claims go through a claims mapping, so the claim names might not always match what you would see in the token. For example, the tid claim is mapped to http://schemas.microsoft.com/identity/claims/tenantid instead.

You can also work directly with the underlying access token from the injected x-ms-token-aad-access-token header.

Use a built-in authorization policy

The created app registration authenticates incoming requests for your Microsoft Entra tenant. By default, it also lets anyone within the tenant to access the application. This approach is fine for many applications. Some applications need to restrict access further by making authorization decisions. Your application code is often the best place to handle custom authorization logic. However, for common scenarios, the Microsoft identity platform provides built-in checks that you can use to limit access.

This section shows how to enable built-in checks using the App Service authentication V2 API. Currently, the only way to configure these built-in checks is by using Azure Resource Manager templates or the REST API.

Within the API object, the Microsoft Entra identity provider configuration has a validation section that can include a defaultAuthorizationPolicy object as in the following structure:

{
    "validation": {
        "defaultAuthorizationPolicy": {
            "allowedApplications": [],
            "allowedPrincipals": {
                "identities": []
            }
        }
    }
}
Property Description
defaultAuthorizationPolicy A group of requirements that must be met in order to access the app. Access is granted based on a logical AND over each of its configured properties. When allowedApplications and allowedPrincipals are both configured, the incoming request must satisfy both requirements in order to be accepted.
allowedApplications An allowlist of string application client IDs that represent the client resource that calls into the app. When this property is configured as a nonempty array, only tokens obtained by an application specified in the list are accepted.

This policy evaluates the appid or azp claim of the incoming token, which must be an access token. See Payload claims.
allowedPrincipals A group of checks that determine if the principal represented by the incoming request can access the app. Satisfaction of allowedPrincipals is based on a logical OR over its configured properties.
identities (under allowedPrincipals) An allowlist of string object IDs that represents users or applications that have access. When this property is configured as a nonempty array, the allowedPrincipals requirement can be satisfied if the user or application represented by the request is specified in the list. There's a limit of 500 characters total across the list of identities.

This policy evaluates the oid claim of the incoming token. See Payload claims.

Also, some checks can be configured through an application setting, regardless of the API version being used. The WEBSITE_AUTH_AAD_ALLOWED_TENANTS application setting can be configured with a comma-separated list of up to 10 tenant IDs, for example, aaaabbbb-0000-cccc-1111-dddd2222eeee.

This setting can require that the incoming token is from one of the specified tenants, as specified by the tid claim. The WEBSITE_AUTH_AAD_REQUIRE_CLIENT_SERVICE_PRINCIPAL application setting can be configured to true or 1 to require the incoming token to include an oid claim. If allowedPrincipals.identities has been configured, this setting is ignored and treated as true because the oid claim is checked against this provided list of identities.

Requests that fail these built-in checks are given an HTTP 403 Forbidden response.

Configure client apps to access your App Service

In the prior sections, you registered your App Service or Azure Function to authenticate users. This section explains how to register native clients or daemon apps in Microsoft Entra. They can request access to APIs exposed by your App Service on behalf of users or themselves, such as in an N-tier architecture. If you only want to authenticate users, the steps in this section aren't required.

Native client application

You can register native clients to request access your App Service app's APIs on behalf of a signed in user.

  1. From the portal menu, select Microsoft Entra ID.

  2. From the left navigation, select Manage > App registrations, then select New registration.

  3. In the Register an application page, enter a Name for your app registration.

  4. In Redirect URI, select Public client/native (mobile & desktop) and type the URL <app-url>/.auth/login/aad/callback. For example, https://contoso.azurewebsites.net/.auth/login/aad/callback.

  5. Select Register.

  6. After the app registration is created, copy the value of Application (client) ID.

    Note

    For a Microsoft Store application, use the package SID as the URI instead.

  7. From the left navigation, select Manage > API permissions. Then select Add a permission > My APIs.

  8. Select the app registration you created earlier for your App Service app. If you don't see the app registration, make sure that you add the user_impersonation scope in the app registration.

  9. Under Delegated permissions, select user_impersonation, and then select Add permissions.

You configured a native client application that can request access your App Service app on behalf of a user.

Daemon client application (service-to-service calls)

In an N-tier architecture, your client application can acquire a token to call an App Service or Function app on behalf of the client app itself, not on behalf of a user. This scenario is useful for non-interactive daemon applications that perform tasks without a logged in user. It uses the standard OAuth 2.0 client credentials grant. For more information, see Microsoft identity platform and the OAuth 2.0 client credentials flow.

  1. From the Azure portal menu, select Microsoft Entra ID.
  2. From the left navigation, select Manage > App registrations > New registration.
  3. In the Register an application page, enter a Name for your app registration.
  4. For a daemon application, you don't need a Redirect URI so you can keep that empty.
  5. Select Register.
  6. After the app registration is created, copy the value of Application (client) ID.
  7. From the left navigation, select Manage > Certificates & secrets. Then select Client secrets > New client secret.
  8. Enter a description and expiration and select Add.
  9. In the Value field, copy the client secret value. After you navigate away from this page, it doesn't appear again.

You can now request an access token using the client ID and client secret. Set the resource parameter to the Application ID URI of the target app. The resulting access token can then be presented to the target app using the standard OAuth 2.0 Authorization header. App Service authentication validates and uses the token as usual to now indicate that the caller is authenticated. In this case, the caller is an application, not a user.

This approach allows any client application in your Microsoft Entra tenant to request an access token and authenticate to the target app. If you also want to enforce authorization to allow only certain client applications, you must perform extra configuration.

  1. Define an App Role in the manifest of the app registration that represents the App Service or Function app you want to protect.

  2. On the app registration that represents the client that needs to be authorized, select API permissions > Add a permission > My APIs.

  3. Select the app registration that you created earlier. If you don't see the app registration, make sure that you added an App Role.

  4. Under Application permissions, select the App Role that you created earlier. Then select Add permissions.

  5. Make sure to select Grant admin consent to authorize the client application to request the permission.

    Similar to the previous scenario (before any roles were added), you can now request an access token for the same target resource, and the access token includes a roles claim containing the App Roles that were authorized for the client application.

Within the target App Service or Function app code, you can now validate that the expected roles are present in the token. App Service authentication doesn't perform this validation. For more information, see Access user claims.

You have configured a daemon client application that can access your App Service app using its own identity.

Best practices

Regardless of the configuration you use to set up authentication, the following best practices keep your tenant and applications more secure:

  • Configure each App Service app with its own app registration in Microsoft Entra.
  • Give each App Service app its own permissions and consent.
  • Avoid permission sharing between environments. Use separate app registrations for separate deployment slots. When you're testing new code, this practice can help prevent issues from affecting the production app.

Migrate to the Microsoft Graph

Some older apps might be set up with a dependency on the deprecated Azure AD Graph, which is scheduled for full retirement. For example, your app code might call Azure AD Graph to check group membership as part of an authorization filter in a middleware pipeline. Apps should move to the Microsoft Graph. For more information, see Migrate your apps from Azure AD Graph to Microsoft Graph.

During this migration, you might need to make some changes to your configuration of App Service authentication. After you add Microsoft Graph permissions to your app registration, you can:

  1. Update the Issuer URL to include the /v2.0 suffix if it doesn't already.

  2. Remove requests for Azure AD Graph permissions from your sign-in configuration. The properties to change depend on which version of the management API you're using:

    • If you're using the V1 API (/authsettings), this setting is in the additionalLoginParams array.
    • If you're using the V2 API (/authsettingsV2), this setting is in the loginParameters array.

    You need to remove any reference to https://graph.windows.net, for example. This change includes the resource parameter, which isn't supported by the /v2.0 endpoint, or any scopes you specifically request that are from the Azure AD Graph.

    You also need to update the configuration to request the new Microsoft Graph permissions you set up for the application registration. You can use the .default scope to simplify this setup in many cases. To do so, add a new sign-in parameter scope=openid profile email https://graph.microsoft.com/.default.

With these changes, when App Service Authentication attempts to sign in, it no longer requests permissions to the Azure AD Graph. Instead, it gets a token for the Microsoft Graph. Any use of that token from your application code also needs to be updated, as described in Migrate your apps from Azure AD Graph to Microsoft Graph.

Next steps