Hello Spring Security Java Config

This guide provides instructions on how to add Spring Security to an existing application without the use of XML.

Table of Contents

Setting up the sample
Securing the application
Conclusion

Setting up the sample

This section outlines how to setup a workspace within Spring Tool Suite (STS) so that you can follow along with this guide. The next section outlines generic steps for how to apply Spring Security to your existing application. While you could simply apply the steps to your existing application, we encourage you to follow along with this guide in order to reduce the complexity.

Obtaining the sample project

Extract the Spring Security Distribution to a known location and remember it as SPRING_SECURITY_HOME.

Import the insecure sample application

In order to follow along, we encourage you to import the insecure sample application into your IDE. You may use any IDE you prefer, but the instructions in this guide will assume you are using Spring Tool Suite (STS).

The completed sample application can be found at SPRING_SECURITY_HOME/samples/javaconfig/helloworld

If you do not have STS installed, download STS from https://spring.io/tools
Start STS and import the sample application into STS using the following steps:
- File→Import
- Existing Maven Projects
- Click Next >
- Click Browse…
- Navigate to the samples (i.e. SPRING_SECURITY_HOME/samples/xml/insecure) and click OK
- Click Finish

Running the insecure application

In the following exercise we will be modifying the spring-security-samples-xml-insecure application. Before we make any changes, it is best to verify that the sample works properly. Perform the following steps to ensure that spring-security-samples-xml-insecure works.

Right click on the spring-security-samples-xml-insecure application
Select Run As→Run on Server
Select the latest tc Server
Click Finish

Verify the application is working by ensuring a page stating TODO Secure this is displayed at http://localhost:8080/sample/

Once you have verified the application runs, stop the application server using the following steps:

In the Servers view select the latest tc Server
Click the stop button (a red square) to stop the application server

Securing the application

Before securing your application, it is important to ensure that the existing application works as we did in Running the insecure application. Now that the application runs without security, we are ready to add security to our application. This section demonstrates the minimal steps to add Spring Security to our application.

Updating your dependencies

In order to resolve Spring Security milestones and release candidates add the Spring Milestone repository. For our example, the repository has already been added for you. In the event you were working on another application, you would need to ensure you add the following to your pom:

pom.xml

<repositories>
  <!-- ... possibly other repository elements ... -->
  <repository>
    <id>spring-milestone</id>
    <name>Spring Milestone Repository</name>
    <url>https://repo.spring.io/milestone</url>
  </repository>
</repositories>

In order to use Spring Security you must add the necessary dependencies. For the sample we will add the following Spring Security dependencies:

pom.xml

<dependencies>
  <!-- ... other dependency elements ... -->
  <dependency>
    <groupId>org.springframework.security</groupId>
    <artifactId>spring-security-web</artifactId>
    <version>5.5.0-RC2</version>
  </dependency>
  <dependency>
    <groupId>org.springframework.security</groupId>
    <artifactId>spring-security-config</artifactId>
    <version>5.5.0-RC2</version>
  </dependency>
</dependencies>

After you have completed this, you need to ensure that STS knows about the updated dependencies by:

Right click on the spring-security-samples-xml-insecure application
Select Maven→Update project…
Ensure the project is selected, and click OK

Creating your Spring Security configuration

The next step is to create a Spring Security configuration.

Right click the spring-security-samples-xml-insecure project in the Package Explorer view
Select New→Class
Enter org.springframework.security.samples.config for the Package
Enter SecurityConfig for the Name
Click Finish
Replace the file with the following contents:

src/main/java/org/springframework/security/samples/config/SecurityConfig.java

package org.springframework.security.samples.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.configuration.*;

@EnableWebSecurity
public class SecurityConfig {

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth
            .inMemoryAuthentication()
                .withUser("user").password("password").roles("USER");
    }
}

The name of the configureGlobal method is not important. However, it is important to only configure AuthenticationManagerBuilder in a class annotated with either @EnableWebSecurity, @EnableGlobalMethodSecurity, or @EnableGlobalAuthentication. Doing otherwise has unpredictable results.

The SecurityConfig will:

Require authentication to every URL in your application
Generate a login form for you
Allow the user with the Username user and the Password password to authenticate with form based authentication
Allow the user to logout
CSRF attack prevention
Session Fixation protection
Security Header integration
- HTTP Strict Transport Security for secure requests
- X-Content-Type-Options integration
- Cache Control (can be overridden later by your application to allow caching of your static resources)
- X-XSS-Protection integration
- X-Frame-Options integration to help prevent Clickjacking
Integrate with the following Servlet API methods

Registering Spring Security with the war

We have created the Spring Security configuration, but we still need to register it with the war. This can be done using the following steps:

Navigate to the Package Explorer view
Right click the org.springframework.security.samples.config package within the spring-security-samples-xml-insecure project
Select New→Class
Enter SecurityWebApplicationInitializer for the Name
Click Finish
Replace the file with the following contents:

src/main/java/org/springframework/security/samples/config/SecurityWebApplicationInitializer.java

package org.springframework.security.samples.config;

import org.springframework.security.web.context.*;

public class SecurityWebApplicationInitializer
      extends AbstractSecurityWebApplicationInitializer {

    public SecurityWebApplicationInitializer() {
        super(SecurityConfig.class);
    }
}

The SecurityWebApplicationInitializer will do the following things:

Automatically register the springSecurityFilterChain Filter for every URL in your application
Add a ContextLoaderListener that loads the SecurityConfig.

Since we were not already using Spring, this is a simple way to add our SecurityConfig. If we were already using Spring, then we should add our SecurityConfig with the reset of our Spring configuration (i.e. a subclass of AbstractContextLoaderInitializer or AbstractDispatcherServletInitializer) and use the default constructor instead.

Exploring the secured application

Start the server as we did in Running the insecure application Now when you visit http://localhost:8080/sample/ you will be prompted with a login page that is automatically generated by Spring Security.

Authenticating to the secured application

Try entering an invalid username and password:

Username invalid
Password invalid

You should see an error message stating that authentication failed. Now try entering a valid username and password:

Username user
Password password

You should now see the page that we wanted to secure.

The reason we can successfully authenticate with Username user and Password password is because that is what we configured in our SecurityConfig.

Displaying the user name

Now that we have authenticated, let’s update the application to display the username. Update the body of index.jsp to be the following:

src/main/webapp/index.jsp

<body>
  <div class="container">
    <h1>This is secured!</h1>
    <p>
      Hello <b><c:out value="${pageContext.request.remoteUser}"/></b>
    </p>
  </div>
</body>

The <c:out /> tag ensures the username is escaped to avoid XSS vulnerabilities Regardless of how an application renders user inputed values, it should ensure that the values are properly escaped.

Refresh the page at http://localhost:8080/sample/ and you will see the user name displayed. This works because Spring Security integrates with the Servlet API methods

Logging out

Now that we can view the user name, let’s update the application to allow logging out. Update the body of index.jsp to contain a log out form as shown below:

src/main/webapp/index.jsp

<body>
  <div class="container">
    <h1>This is secured!</h1>
    <p>
      Hello <b><c:out value="${pageContext.request.remoteUser}"/></b>
    </p>
    <c:url var="logoutUrl" value="/logout"/>
    <form class="form-inline" action="${logoutUrl}" method="post">
      <input type="submit" value="Log out" />
      <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}"/>
    </form>
  </div>
</body>

In order to help protect against CSRF attacks, by default, Spring Security Java Configuration log out requires:

the HTTP method must be a POST
the CSRF token must be added to the request. You can access it on the ServletRequest using the attribute _csrf as illustrated above.

If you were using Spring MVC’s tag library or Thymeleaf, the CSRF token is automatically added as a hidden input for you.

Refresh the page at http://localhost:8080/sample/ and you will see the log out button. Click the logout button and see that the application logs you out successfully.

Conclusion

You should now know how to secure your application using Spring Security without using any XML. To learn more refer to the Spring Security Guides index page.