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Enable your Java Servlet web app to sign in users to your Microsoft Entra tenant with the Microsoft identity platform

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Overview

This sample demonstrates a Java Servlet web app that signs users in to your Microsoft Entra tenant using the Microsoft Authentication Library (MSAL) for Java. It also demonstrates how to step-up the authentication challenge by requiring multi-factor authentication (MFA) for certain routes.

Overview

Note Make sure you understand the basic web site authentication sample first. This shows how to sign users in.

Scenario

This web application shows how to challenge users to authenticate for some routes and challenge users to authenticate and perform MFA for other routes.

  1. Some web site actions (routes) need the user to be authenticated and others require the user to be authenticated and to have passed the MFA challenge.
  2. An authentication context c1 has already been created and associated with MFA
  3. If an MFA route is accessed by the user, the ID token is checked for proof of MFA - a claim named arcs with the value C1
  4. If an ID token does not exist (i.e., user is not authenticated at all) or if the claim does not exist (they have not passed the MFA challenge), the user is challenged to MFA. This means that they are redirected to the authorization page and a claims challenge is appended to the authorization URI.

Example claim challenge: {"id_token":{"acrs":{"essential":true,"value":"c1"}}}

Note MFA is one of the many Conditional Access controls available. Any of them may be used.

Contents

File/folder Description
AppCreationScripts/ Scripts to automatically configure Microsoft Entra app registrations.
src/main/java/com/microsoft/azuresamples/msal4j/authwebapp/ This directory contains the classes that define the web app's backend business logic.
src/main/java/com/microsoft/azuresamples/msal4j/authservlets/ This directory contains the classes that are used for sign in and sign out endpoints.
____Servlet.java All of the endpoints available are defined in .java classes ending in ____Servlet.java.
src/main/java/com/microsoft/azuresamples/msal4j/helpers/ Helper classes for authentication.
AuthenticationFilter.java Redirects unauthenticated requests to protected endpoints to a 401 page.
src/main/resources/authentication.properties Microsoft Entra ID and program configuration.
src/main/webapp/ This directory contains the UI (JSP templates)
CHANGELOG.md List of changes to the sample.
CONTRIBUTING.md Guidelines for contributing to the sample.
LICENSE The license for the sample.

Prerequisites

Setup

1. Clone or download this repository

From your shell or command line:

git clone https://github.com/Azure-Samples/ms-identity-msal-java-samples.git
cd 3-java-servlet-web-app/1-Authentication/sign-in-auth-context

or download and extract the repository .zip file.

⚠️ To avoid file path length limitations on Windows, clone the repository into a directory near the root of your hard drive.

2. Create a Microsoft Entra application registration for the website

Note This is identical to the basic web site authentication sample.

Details here

Register a new web app in the Microsoft Entra admin center. Following this guide, you must:

  1. Navigate to the Microsoft identity platform for developers App registrations page.
  2. Select New registration.
  3. In the Register an application page that appears, enter your application's registration information:
    • In the Name section, enter a meaningful application name that will be displayed to users of the app, for example java-servlet-webapp-authentication.
    • Under Supported account types, select an option.
      • Select Accounts in this organizational directory only if you're building an application for use only by users in your tenant (single-tenant).
      • Select Accounts in any organizational directory if you'd like users in any Microsoft Entra tenant to be able to use your application (multi-tenant).
      • Select Accounts in any organizational directory and personal Microsoft accounts for the widest set of customers (multi-tenant that also supports Microsoft personal accounts).
    • Select Personal Microsoft accounts for use only by users of personal Microsoft accounts (e.g., Hotmail, Live, Skype, Xbox accounts).
    • In the Redirect URI section, select Web in the combo-box and enter the following redirect URI: http://localhost:8080/msal4j-servlet-auth/auth/redirect.
  4. Select Register to create the application.
  5. In the app's registration screen, find and note the Application (client) ID. You use this value in your app's configuration file(s) later in your code.
  6. Select Save to save your changes.
  7. In the app's registration screen, click on the Certificates & secrets blade in the left to open the page where we can generate secrets and upload certificates.
  8. In the Client secrets section, click on New client secret:
    • Type a key description (for instance app secret),
    • Select one of the available key durations (In 1 year, In 2 years, or Never Expires) as per your security concerns.
    • The generated key value will be displayed when you click the Add button. Copy the generated value for use in the steps later.
    • You'll need this key later in your code's configuration files. This key value will not be displayed again, and is not retrievable by any other means, so make sure to note it from the Microsoft Entra admin center before navigating to any other screen or blade.

Configure the web app (java-servlet-webapp-authentication) to use your app registration

Open the project in your IDE to configure the code.

In the steps below, "ClientID" is the same as "Application ID" or "AppId".

  1. Open the ./src/main/resources/authentication.properties file
  2. Find the string {enter-your-tenant-id-here}. Replace the existing value with you tenant id
  3. Find the string {enter-your-client-id-here} and replace the existing value with the application ID (clientId) of the java-servlet-webapp-authentication application copied from the Microsoft Entra admin center.
  4. Find the string {enter-your-client-secret-here} and replace the existing value with the key you saved during the creation of the java-servlet-webapp-authentication app, in the Microsoft Entra admin center.

3. Setup the MFA Conditional Access Context

  1. In the Microsoft Entra admin center, type Microsoft Entra Conditional Access in the search bar and select it.

CA

Note: this is a different Microsoft Entra admin center section than Microsoft Entra ID

  1. Go to the Authentication Contexts page, and click on New Authentication context. Give it a name (e.g. "MFA") and select an ID of the Auth context from the list, for example c1. Ensure the "Publish To Apps" checkbox is checked. Make a note of the ID.

Note: We have already configured the conditional access auth context ID to c1 in the code for you but you can modify it in the authentication.properties file. Modify the value of app.protect.authContextIdMfa to any ID you want but make sure it matches the ID you chose in the portal.

  1. Now go to Policies and create a new Conditional Access policy.
    • Name it MFA-app-policy or something meaningful.
    • Select All Users or a subset of users.
    • Select Target Resources and set it to Authentication Context. Then add the context you just created.
    • You can skip the "Conditions" part of the flow. This policy will apply to all calls.
    • In Grant, check the Require Multi-Factor Authentication policy.
    • You can skip Session.
    • Click the Select button then click Create.

CA-MFA

Running The Sample

Build .war File Using Maven

  1. Navigate to the directory containing the pom.xml file for this sample (the same directory as this README), and run the following Maven command: 
    mvn clean package
  2. This should generate a .war file which can be run on a variety of application servers

Deploying the Sample

The homepage for the sample is http://localhost:8080/msal4j-servlet-auth as seen in the authentication.properties file

Our samples can be deployed to a number of application servers, such as Tomcat, WebLogic, or Webshpere, and MSAL Java itself can generally be integrated into existing applications without changes to your existing deployment set up.

You can find instructions for deploying our samples here on MSAL Java's Github wiki.

signed-in

Explore the sample

  • In authwebapp there are 2 protected routes: token_details requires simple authentication and token_details_mfa which requires MFA.
  • The orchestration logic is in the AuthenticationFilter. It figures out the state of the user (authenticated, authenticated + MFA, not authenticated) and the requirements of the route (based on configuration).
  • If the auth requirement is not met, the user is challenged, meaning they are redirected to the Identity Provider (Microsoft Entra).
  • To understand if a user meets the authentication context (MFA), the sample looks at the ID Token for a claim named acrs and value c1.
  • To challenge a user if they are not authenticated, the sample adds a claims challenge to the authorization URI claims={"id_token":{"acrs":{"essential":true,"value":"c1"}}}

ℹ️ Did the sample not work for you as expected? Did you encounter issues trying this sample? Then please reach out to us using the GitHub Issues page.

We'd love your feedback!

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Next Steps or Deploy to Azure

As next steps, we can now either get an Access Token for the users we signed-in in this tutorial, or we can proceed to deploy this app to Azure App Service.

Community Help and Support

Use Stack Overflow to get support from the community. Ask your questions on Stack Overflow first and browse existing issues to see if someone has asked your question before. Make sure that your questions or comments are tagged with [microsoft-entra-id ms-identity java msal].

If you find a bug in the sample, please raise the issue on GitHub Issues.

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

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