Configure Azure AD authentication - Azure App Service

Option 1: Create a new app registration automatically

Use this option unless you need to create an app registration separately. You can customize the app registration in Azure AD once it's created.

Select Authentication in the menu on the left. Select Add identity provider .

Select Microsoft in the identity provider dropdown. The option to create a new registration is selected by default. You can change the name of the registration or the supported account types.

A client secret will be created and stored as a slot-sticky application setting named MICROSOFT_PROVIDER_AUTHENTICATION_SECRET . You can update that setting later to use Key Vault references if you wish to manage the secret in Azure Key Vault.

If this is the first identity provider configured for the application, you'll also be prompted with an App Service authentication settings section. Otherwise, you may move on to the next step.

These options determine how your application responds to unauthenticated requests, and the default selections will 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 . To learn more about these options, see Authentication flow .

(Optional) Select Next: Permissions and add any Microsoft Graph permissions needed by the application. These will be added to the app registration, but you can also change them later.

Select Add .

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

For an example of configuring Azure AD sign-in for a web app that accesses Azure Storage and Microsoft Graph, see this tutorial .

Option 2: Use an existing registration created separately

You can configure App Service authentication to use an existing app registration. 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 Azure AD tenant.

You want to use an app registration from a different Azure AD tenant than the one your app is in.

The option to create a new registration isn't available for government clouds.

Step 1: Create an app registration in Azure AD for your App Service app

During creation of the app registration, collect the following information which you'll need later when you configure the authentication in the App Service app:

Client ID

Tenant ID

Client secret (optional, but recommended)

Application ID URI

The instructions for creating an app registration depend on if you're using a workforce tenant or a customer tenant (Preview) . Use the tabs below to select the right set of instructions for your scenario.

To register the app, perform the following steps:

Sign in to the Azure portal , search for and select App Services , and then select your app. Note your app's URL . You'll use it to configure your Azure Active Directory app registration.

Navigate to your tenant in the portal:

Workforce tenant Customer tenant (Preview)

If you do not already have a customer tenant, create one by following the instructions in Create a customer identity and access management (CIAM) tenant .

Switch your directory in the Azure portal to the customer tenant.

Because you're working in two tenant contexts (the tenant for your subscription and the customer tenant), you may want to open the Azure portal in two separate tabs of your web browser. Each can be signed into a different tenant.

From the portal menu, select Azure Active Directory .

On the "Overview" screen, make note of the Tenant ID , as well as the Primary domain .

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

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

In Supported account types , select the account type that can access this application.

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 .

Select Register .

After the app registration is created, copy the Application (client) ID and the Directory (tenant) ID for later.

Under Implicit grant and hybrid flows , enable ID tokens to allow OpenID Connect user sign-ins from App Service. Select Save .

(Optional) From the left navigation, select Branding & properties . In Home page URL , enter the URL of your App Service app and select Save .

From the left navigation, select Expose an API > Set > Save . This value uniquely identifies the application when it's used as a resource, allowing tokens to be requested that grant access. It's used as 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 multi-tenant app, you must provide a custom URI. To learn more about accepted formats for App ID URIs, see the app registrations best practices reference .

Select Add a scope .

In Scope name , enter user_impersonation .

In Who can consent , select Admins and users if you want to allow users to consent to this scope.

In the text boxes, enter the consent scope name and description you want users to see on the consent page. For example, enter Access <application-name> .

Select Add scope .

(Optional) To create a client secret:

From the left navigation, select Certificates & secrets > Client secrets > New client secret .

Enter a description and expiration and select Add .

In the Value field, copy the client secret value. It won't be shown again once you navigate away from this page.

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

Finish setting up your app registration:

Workforce tenant Customer tenant (Preview)

Create a user flow, which defines an authentication experience that can be shared across app registrations in the tenant:

Navigate back to the tenant and select External identities .

(Optional) Configure identity providers under All identity providers . See Authentication methods and identity providers for customers for details on the available options.

Select User flows > New user flow .

Enter a name such as "SignUpSignIn", and then select the identity providers and user attributes you wish to use in this flow. When done, select Create .

These steps are also covered in Create a sign-up and sign-in user flow .

Configure your app registration to work with the user flow:

Select the user flow that you just created.

Select Applications > Add application .

Search for the app registration you created earlier, select it, and then select Select .

These steps are also covered in Add your application to the user flow .

Switch your directory back to the tenant that includes your subscription and App Service app so that you can perform the next steps.

Step 2: Enable Azure Active Directory in your App Service app

From the left navigation, select Authentication > Add identity provider > Microsoft .

Select the Tenant type of the app registration you created.

Configure the app to use the registration you created, using the instructions for the appropriate tenant type:

Workforce tenant Customer tenant (Preview)

For App registration type , choose one of the following:

Pick an existing app registration in this directory : Choose an app registration from the current tenant and automatically gather the necessary app information. The system will attempt to create a new client secret against the app registration and automatically configure your app to use it. A default issuer URL is set based on the supported account types configured in the app registration. If you intend to change this default, consult the following table.

Provide the details of an existing app registration : Specify details for an app registration from another tenant or if your account doesn't have permission in the current tenant to query the registrations. For this option, you must manually fill in the configuration values according to the following table.

The authentication endpoint for a workforce tenant should be a value specific to the cloud environment . For example, a workforce tenant in global Azure would use "https://login.microsoftonline.com" as its authentication endpoint. Make note of the authentication endpoint value, as it's needed to construct the right Issuer URL .

For a customer tenant, you must manually fill in the configuration values according to the following table.

The authentication endpoint for a customer tenant should be https://<tenant-subdomain>.ciamlogin.com , replacing <tenant-subdomain> with the default subdomain for the tenant. The default subdomain is part of the primary domain for the tenant, which should be of the form <tenant-subdomain>.onmicrosoft.com and was set during tenant creation. For example, if the tenant had the domain "contoso.onmicrosoft.com", the tenant subdomain would be "contoso", and the authentication endpoint would be "https://contoso.ciamlogin.com". Make note of the authentication endpoint value, as it's needed to construct the right Issuer URL .

When filling in the configuration details directly, use the values you collected during the app registration creation process:

Field Description Client Secret Use the client secret you generated in the app registration. With a client secret, hybrid flow is used and the App Service will return access and refresh tokens. When the client secret isn't set, implicit flow is used and only an ID token is returned. These tokens are sent by the provider and stored in the App Service authentication token store. Issuer URL Use


   <authentication-endpoint>/<tenant-id>/v2.0

, and replace <authentication-endpoint> with the authentication endpoint you determined in the previous step for your tenant type and cloud environment, also replacing <tenant-id> with the Directory (tenant) ID in which the app registration was created. For applications that use Azure AD v1, omit


   /v2.0

in the URL.

This value is used to redirect users to the correct Azure AD tenant, as well as to download the appropriate metadata to determine the appropriate token signing keys and token issuer claim value for example. Any configuration other than a tenant-specific endpoint will be treated as multi-tenant. In multi-tenant configurations, no validation of the issuer or tenant ID is performed by the system, and these checks should be fully handled in your app's authorization logic . Allowed Token Audiences This field is optional. The configured Application (client) ID is always implicitly considered to be an allowed audience. If your application represents an API that will be called by other clients, you should also add the Application ID URI that you configured on the app registration. There's a limit of 500 characters total across the list of allowed audiences.

The client secret will be stored as a slot-sticky application setting named MICROSOFT_PROVIDER_AUTHENTICATION_SECRET . You can update that setting later to use Key Vault references if you wish to manage the secret in Azure Key Vault.

If this is the first identity provider configured for the application, you'll also be prompted with an App Service authentication settings section. Otherwise, you may move on to the next step.

Select Add .

Authorize requests

By default, App Service Authentication only handles authentication, determining if the caller is who they say they are. Authorization, determining if that caller should have access to some resource, is an extra step beyond authentication. You can learn more about these concepts from Microsoft identity platform authorization basics .

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

Multi-tenant 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 multi-tenant scenario, it doesn't validate which tenant the request comes from. An app may need to be limited to specific tenants, based on if the organization has signed up for the service, for example. See the Microsoft identity platform multi-tenant guidance .

Perform validations from application code

When you perform authorization checks in your app code, you can leverage the claims information that App Service Authentication makes available . 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 may 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 Azure AD tenant. By default, it also lets anyone within the tenant to access the application, which is fine for many applications. However, 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 via Azure Resource Manager templates or the REST API .

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

"validation": { "defaultAuthorizationPolicy": { "allowedApplications": [], "allowedPrincipals": { "identities": []


    defaultAuthorizationPolicy

A grouping 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 representing the client resource that is calling into the app. When this property is configured as a nonempty array, only tokens obtained by an application specified in the list will be accepted.

This policy evaluates the


    appid

azp

claim of the incoming token, which must be an access token. See the Microsoft Identity Platform claims reference .


    allowedPrincipals

A grouping of checks that determine if the principal represented by the incoming request may 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 representing 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.

This policy evaluates the

oid

claim of the incoming token. See the Microsoft Identity Platform claims reference .

Additionally, 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 (e.g., "559a2f9c-c6f2-4d31-b8d6-5ad1a13f8330,5693f64a-3ad5-4be7-b846-e9d1141bcebc") to 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. This setting is ignored and treated as true if allowedPrincipals.identities has been configured (since 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 Azure AD so that they can request access to APIs exposed by your App Service on behalf of users or themselves, such as in an N-tier architecture. Completing the steps in this section isn't required if you only wish to authenticate users.

Native client application

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

From the portal menu, select Azure Active Directory .

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

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

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

Select Register .

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

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

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

Select the app registration you created earlier for your App Service app. If you don't see the app registration, make sure that you've added the user_impersonation scope in Create an app registration in Azure AD for your App Service app .

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

You have now 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.

From the portal menu, select Azure Active Directory .

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

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

For a daemon application, you don't need a Redirect URI so you can keep that empty.

Select Register .

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

From the left navigation, select Certificates & secrets > Client secrets > New client secret .

Enter a description and expiration and select Add .

In the Value field, copy the client secret value. It won't be shown again once you navigate away from this page.

You can now request an access token using the client ID and client secret by setting 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 , and App Service authentication will validate and use the token as usual to now indicate that the caller (an application in this case, not a user) is authenticated.

At present, this allows any client application in your Azure AD 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 some extra configuration.

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

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

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

Under Application permissions , select the App Role you created earlier, and then select Add permissions .

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 will include 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 (this isn't performed by App Service authentication). For more information, see Access user claims .

You have now 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 will keep your tenant and applications more secure:

Configure each App Service app with its own app registration in Azure AD.

Give each App Service app its own permissions and consent.

Avoid permission sharing between environments by using 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 may also have been set up with a dependency on the deprecated Azure AD Graph , which is scheduled for full retirement. For example, your app code may have called Azure AD graph to check group membership as part of an authorization filter in a middleware pipeline. Apps should move to the Microsoft Graph by following the guidance provided by Azure AD as part of the Azure AD Graph deprecation process . In following those instructions, you may need to make some changes to your configuration of App Service authentication. Once you have added Microsoft Graph permissions to your app registration, you can:

Update the Issuer URL to include the "/v2.0" suffix if it doesn't already. See Enable Azure Active Directory in your App Service app for general expectations around this value.

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 would be in the


    additionalLoginParams

array.

If you're using the V2 API (


    /authsettingsV2

), this would be in the


    loginParameters

array.

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

You would 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 will no longer request permissions to the Azure AD Graph, and instead it will get a token for the Microsoft Graph. Any use of that token from your application code would also need to be updated, as per the guidance provided by Azure AD .

Next steps

App Service Authentication / Authorization overview .

Tutorial: Authenticate and authorize users end-to-end in Azure App Service

Tutorial: Authenticate and authorize users in a web app that accesses Azure Storage and Microsoft Graph

Tutorial: Authenticate and authorize users end-to-end in Azure App Service