how to implement role-based security in microservices architecture [closed]

Answer 1

Question is wide at the moment as the nature of the traffic to your microservices is not clear.

• Assuming that all external traffic coming via your API gateway to your microservices.

  • You don't need to validate the JWT twice once in API gateway and then again in your internal microservice. If the JWT is invalid , the request will never reach your microservice
  • Then API gateway propagate the roles. In your microservice, you initialise the spring security context using the roles passed in the header. It will allow you to use @PreAuthorize etc

• Assuming that external traffic can come via your API gateway as well as directly to your microservices.

  • Now you need to verify it in both API gateway and in your microservices

Update

• I don't have knowledge about Zuul API gateway. This is just addressing the following:

I have tried to use @PreAuthorize but it's not working out of the gateway (obviously in order to make it work I have to set a Spring Security authentication object in the SecurityContextHolder in my microservices and populate it with authorities).

    public class PreAuthenticatedUserRoleHeaderFilter 
        extends GenericFilterBean {

    public void doFilter(ServletRequest servletRequest, 
                         ServletResponse servletResponse,
                         FilterChain chain) 
            throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) servletRequest;
        String rolesString = //extract the roles
        String userName = // extract the username

        List<GrantedAuthority> authorities 
           = AuthorityUtils.commaSeparatedStringToAuthorityList(rolesString);


        PreAuthenticatedAuthenticationToken authentication 
                = new PreAuthenticatedAuthenticationToken(
                                    userName, null, authorities);
        SecurityContextHolder.getContext().setAuthentication(authentication);
        chain.doFilter(servletRequest, servletResponse);
    }
}

    @Configuration
    @EnableGlobalMethodSecurity(prePostEnabled = true, securedEnabled = true, 
        jsr250Enabled = true)
    public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        PreAuthenticatedUserRoleHeaderFilter authFilter
                = new PreAuthenticatedUserRoleHeaderFilter();
        http.
                antMatcher("/**")
                .csrf()
                .disable()
                .sessionManagement()
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
                .and()
                .addFilterBefore(authFilter, 
                                 BasicAuthenticationFilter.class)
                .authorizeRequests()
                .anyRequest()
                .authenticated();
      }

    }

Answer 2

If you'r API gateway is also the one who create's and sign JWT token's with private key's and to authenticate you use public key's from API gateway then you are the one who specifies structure of that JWT token and you should be able to encode roles into that JWT (it could be scope parameter for example but all possible scope's are usually accessible by all users). Then you can configure spring boot to automaticaly resolve group role from that JWT (set SecurityContextHolder role's right) and @PreAuthorize annotation can be used without any modification.

If you'r API gateway is only verifying JWT token's against 3rd party authorization server (the server which signed and structured that JWT) with public key's from this server you must implement some custom mechanism for role-based access. One that come's to my mind is to implement second level Oauth2 authentication which would be only used with request's between your microservice's and API gateway using some kind of 'inner' JWT. For example see following image:

Since you define how structure of inner JWT should look by your API gateway code you can set custom attribute's like role: (admin, user etc..). This can be resolved for example from user name, id, email which you are provided from outer JWT from 3rd party authorization server. Therefore you would need to keep some mapping inside API gateway code like:

(userId: 12563) => Admin group
(userId: 45451) => User group

Since your micro-services use JWT for authentication you can use spring boot resource server to setup authentication and configure it to resolve group's (object you mentioned inside SecurityContextHolder) automatically from your custom structured inner JWT. This way you could simply use @PreAuthorize annotation inside your micro-service's and therefore you would not have to create custom annotation's. Note that this is only supposed to solve second case i have specified in first case you are in control of JWT token already.

Answer 3

In Spring5 microservices you will be able to find a base to develop a microservice architecture with several of the requisites you are looking for:

• Registry server using Eureka.
• Gateway server with Zuul.

Regarding to security, I have developed two different microservices:

• Spring Oauth2 with Jwt
• Spring Jwt multi-application security service to work with access and refresh Jwt tokens, with several customizations like: definition of the content of every one, work with JWS or JWE, etc

Most important ones are well documented using Swagger, as you can see here, and all documented APIs are accessible using an unique gateway Url.

For all classes of every microservice, Junit tests were developed.

---

Security

At this point, I took several decisions:

1. Is not the gateway the microservice that verifies the security.

Because use the gateway as "firewall" is a less flexible approach. I wanted to decide which microservices need security and every one should manage internally the roles can access to every endpoint. In summary, every microservice has to work with the authorization/authentication but it don't need to know how that functionality is done.

2. Specific microservice to deal with the security

As I told you, I developed 2 different ones, because I wanted to "play" with different options/approaches. The most important advantage is the encapsulation, if "tomorrow" I decide to change Jwt by any other option, I will only need to modify those ones, the microservices that use them will keep the same code (I will explain you soon how the integration was done)

---

Security integration example

I will explain how the security functionality was integrated between:

• Pizza service easy microservice developed as part of the architecture.
• Spring Jwt

1. Every application that manages user and roles, will include in the security microservice a folder similar to the next one, to define its models, repositories to get the required information, etc

2. Global endpoints of the security microservice are defined here. As you can see, they work basically with 2 Dtos:

• AuthenticationInformationDto
• UsernameAuthoritiesDto

The main advantage, only the security microservice knows the details about how that functionality was done, the other ones that use it will receive a well known Dtos with the required information.

3. In pizza-service, the security integration is mainly defined in the next 3 classes:

• SecurityContextRepository to get authorization token from the header and send it to the SecurityManager.
• SecurityManager call to security-jwt-service with the provided "authorization token" (it doesn't know if it is Jwt or any other thing) and receives a well know UsernameAuthoritiesDto (transforming it into an object of the Spring class UsernamePasswordAuthenticationToken)
• WebSecurityConfiguration global security configuration.

Now you can include in your endpoints the required role based security:

• Controller example
• Custom PreAuthorize annotation

---

Final considerations

1. pizza-service was developed using Webflux, you can see an equivalent integration based on a MVC microservice one in order-service here (in this case I used the "other security service" but is easy to adapt it).

2. To improve the security and follow the "Oauth approach", the requests to security-jwt-service need to include the Basic authentication too. As you can see in SecurityManager class:

   private String buildAuthorizationHeader(String username, String password) {
     String auth = username + ":" + password;
     byte[] encodedAuth = Base64.getEncoder().encode(auth.getBytes());
     return "Basic " + new String(encodedAuth);
   }
   

The table in database to store that information is the same one used to manage the security configuration of every application: security.jwt_client_details

Answer 4

Role based authorization is avoided these days and scope based authorization is preferred with something like service1.read, service2.full_access scopes. You could either: move role based authorization into each service and away from identity server, convert to scope based authorization, move role based authorization job to respective service rather than relay on identity server.

You can user reference token flow and invalidate token when changes occurs in your role/rights, this will help explaining it