Streamlining Authentication and Authorization: Auth0 and Spring Boot

Use Case

• You have built an awesome app and you want to add user authentication and authorization. Your users should be able to log in either with a username/password or with their social accounts (such as Facebook or Twitter). You want to retrieve the user’s profile after the login so you can customize the UI and apply your authorization policies.
• You have built an API and you want to secure it with OAuth 2.0.
• You have more than one app, and you want to implement Single Sign-on (SSO).
• You have built a JavaScript front-end app and a mobile app, and you want them both to securely access your API.
• You have a web app that needs to authenticate users using Security Assertion Markup Language (SAML).
• You believe passwords are broken and you want your users to log in with one-time codes delivered by email or SMS.
• If one of your user’s email addresses is compromised in some site’s public data breach, you want to be notified, and you want to notify the users and/or block them from logging in to your app until they reset their password.
• You want to act proactively to block suspicious IP addresses if they make consecutive failed login attempts, in order to avoid DDoS attacks.
• You are part of a large organization that wants to federate your existing enterprise directory service to allow employees to log in to the various internal and third-party applications using their existing enterprise credentials.
• You don’t want (or you don’t know how) to implement your own user management solution. password resets, creating, provisioning, blocking, and deleting users, and the UI to manage all these. You just want to focus on your app.
• You want to enforce multi-factor authentication (MFA) when your users want to access sensitive data.
• You are looking for an identity solution that will help you stay on top of the constantly growing compliance requirements of SOC2, GDPR, PCI DSS, HIPAA, and others.

Authentication and Authorization Flows

Auth0 uses the OpenID Connect (OIDC) Protocol and OAuth 2.0 Authorization Framework to authenticate users and get their authorization to access protected resources. With Auth0, you can easily support different flows in your own applications and APIs without worrying about OIDC/OAuth 2.0 specifications or other technical aspects of authentication and authorization.

Authorization Code Flows

Regular web apps are server-side apps where the source code is not publicly exposed, they can use the Authorization Code Flow, which exchanges an Authorization Code for a token. Your app must be server-side because during this exchange, you must also pass along your application’s Client Secret, which must always be kept secure, and you will have to store it in your client.

Fig. Authentication Code Flow Chart

• The user clicks login within the regular web application.
• Auth0’s SDK redirects the user to the Auth0 Authorization Server (/authorize).
• Your Auth0 Authorization Server redirects the user to the login and Authorization prompt.
• The user authenticates using one of the configured login options and may see a consent page listing the permissions Auth0 will give to the regular web application.
• Your Auth0 Authorization Server redirects the user back to the application with an Authorization code, which is good for one use.
• Auth0’s SDK sends this code to the Auth0 Authorization Server (/OAuth/token) along with the application’s Client ID and Client Secret.
• Your Auth0 Authorization Server verifies the code, Client ID, and Client Secret.
• Your Auth0 Authorization Server responds with an ID Token and Access Token (and optionally, a Refresh Token).
• Your application can use the Access Token to call an API to access information about the user.
• The API responds with the requested data.

Implementation Steps

Now let’s get started with the implementation process of integrating Auth0 with Spring Boot:

Step 1: Configure Auth0

1. Log in to your Auth0 account and navigate to the Applications section.
2. Create a new application and choose the appropriate application type (Single Page Application, Regular Web Application, etc.).
3. Configure the necessary settings, such as allowed callback URLs and logout URLs, based on your Spring Boot application’s requirements.
4. Note down the “Client ID” and “Client Secret” generated by Auth0, as they will be needed in the Spring Boot application.

Step 2: Add Dependencies

1. Open your Spring Boot project in your preferred IDE.
2. Add the following dependencies in your pom.xml (for Maven) or build.gradle (for Gradle) file:

• spring-boot-starter-web
• spring-boot-starter-security
• com.auth0:auth0-spring-security-api:<version>

Step 3: Configure Spring Security

1. Create a new Java class, SecurityConfig.java, to configure Spring Security settings.
2. Annotate the class with @EnableWebSecurity and @EnableGlobalMethodSecurity(prePostEnabled = true) to enable security configurations.
3. Override the configure(HttpSecurity http) method to define the security rules and authorize access to different endpoints.

Step 4: Configure Auth0 Integration

1. Create a new Java class, Auth0Config.java, to configure the integration with Auth0.
2. Use the @Configuration annotation to mark the class as a configuration class.
3. In the class, create a @Bean method to configure the Auth0JwtAuthenticationProvider by providing the Auth0 issuer URL and audience.
4. Inject the Auth0JwtAuthenticationProvider bean into the SecurityConfig class and configure the authentication provider using auth.authenticationProvider().

Step 5: Implement Controller and Endpoints

1. Create Spring MVC controllers to handle different endpoints in your application.
2. Annotate the controller methods with appropriate security annotations (@PreAuthorize, @RolesAllowed, etc.) to enforce authorization rules.
3. Use the Authentication object to retrieve user information and perform additional checks, if needed.

Step 6: Test the Integration

1. Start your Spring Boot application.
2. Access the secured endpoints and observe the behavior based on the configured security rules.
3. Verify that the authentication and authorization process works as expected, leveraging Auth0 for user authentication.