How Basic Authentication works in Spring Security?

I have already described the Spring Security Authentication Architecture in a previous article.  So i am not going to repeat the same thing again in this article. If you do not know about the general authentication architecture of spring security, it is highly recommend to take a look at article about Spring Security Authentication Architecture before continue with this article.

Here it is expected to point out the major components and classes that are related to HTTP Basic authentication. Here is the architectural flow of HTTP Basic Authentication implementation in spring security.

How to configure Spring Security for HTTP Basic Authentication?

When you use the httpBasic() configuration element (In HttpSecurity configuration), Spring Security  BasicAuthenticationFilter comes into action.

In Spring Security, the following two classes are the main core (important) classes that supports to implement HTTP Basic Authentication.

• BasicAuthenticationFilter
• BasicAuthenticationEntryPoint

A BasicAuthenticationEntryPoint strategy will be configured into the ExceptionTranslationFilter on startup.

Here is the Spring Security Basic Authentication Architecture diagram.

Here you will notice that, if the authentication mechanism is HTTP Basic, then the related AuthenticationFilter class will be the BasicAuthenticationFilter.  It accepts the HTTP request (for user authentication) and extracts the username and password (from http request).

Then it creates the Authentication Token (UsernamePasswordAuthenticationToken) using the extracted user credentials. After that it delegates the Authentication request  to the AuthenticationManager and waits until the authentication response comes from the authentication manager.

Response from AuthenticationManager

If you just check the source code of the AuthenticationManager interface, you may notice that  it can produce two types of responses. Therefore BasicAuthenticationFilter can expect these two types of responses from the authentication manager.

• returns fully populated Authenticated Object (On successful Authentication)
• throws an AuthenticationException  (On Authentication Failure)

If the authentication is successful, a fully populated authentication object will be returned and it will be stored in the SecurityContext. 

 If any authentication failure happens, it will throw an AuthenticationException. This AuthenticationException will be initially received and handled by the ExceptionTranslationFilter and it will be delegated to the BasicAuthenticationEntryPoint  for further consideration/action.

 

What is BasicAuthenticationEntryPoint?

If any AuthenticationException is occurred in spring security filter chain, it will be delegated to the the related/configured AuthenticationEntryPoint for further action.

If the Authentication mechanism is HTTP Basic, then the relevant AuthenticationEntryPoint will be BasicAuthenticationEntryPoint.  This will accepts the AuthenticationException occurred during the authentication process (HTTP Basic) and will help to generate user response with meaningful headers to notify the client about the authentication failure.

Ok. Lets  look at a sample spring security project that uses http basic authentication for securing its REST Api endpoints. 

 

The fully source code of this example can be found at  GitHub – Click here to go to project repository

Here is the project structure.

 

SpringSecurityConfig.java

According to the spring configuration, it uses HTTP Basic Authentication (http.httpBasic()) and any request for any resource should be authenticated. In addition, It creates three users in memory with following roles and credentials.

Username	Password	Roles
app_user	test123	ROLE_USER
admin	test123	ROLE_USER, ROLE_ADMIN
chathuranga	test123	ROLE_USER, ROLE_ADMIN

 

PasswordEncoder in Spring Security 5

 @Bean
 public NoOpPasswordEncoder passwordEncoder() 
 {
    return (NoOpPasswordEncoder) NoOpPasswordEncoder.getInstance();
 }

 

When we use Spring Security 5, we need to explicitly provide the PasswordEncoder that our passwords are encoded with. It was not a requirement with Spring Security 4.x versions. But this has been mandatory in Spring Security 5 regardless of the AuthenticationProvider. Therefore this guaranteed that your passwords are stored in encrypted format and clear text password are no longer supported.

But when it comes to creating in-memory authentication provider for testing and development purposes, you might need to declare clear text password in the source code as i have done in this example. Since the Spring Security 5 forces to explicitly declare type of PasswordEncoder regardless of the authentication provider., we can use NoOpPasswordEncoder  as the PasswordEncoder.

NoOpPasswordEncoder is a password encoder that does nothing. Useful for testing where working with plain text passwords.

 

So just look at the RestApiController. You will see a list of supported REST Api endpoints for each user role.

 

 

How to deploy the application?

You can get the fully source code of the application through the following Github location.

https://github.com/chathurangat/spring-security-http-basic-authentication

download the source files and cd into the project directory.

cd   spring-security-http-basic-authentication

After that you can tun following command to deploy and run the application.

mvn spring-boot:run

 

Now you can access any of above endpoints with valid user credentials (as listed in above table) with HTTP Basic Authentication. Sample postman request can be shown as follows.

 

Authorization     Basic base64encode(username:password)

 

Hope that after reading this article, you have improved your understanding of how HTTP Basic authentication is used in spring security  to secure REST api endpoints.

• Spring Security