Spring Security: Propagating Security Context to Spawned Threads

PROBLEM

Let’s assume we have the following Parent class…

@Service
class Parent {
    @Autowired
    Child child

    void run() {
        println "Parent: ${SecurityContextHolder.context.authentication?.principal}"

        child.run()

        println "Parent: Done"
    }
}

… and Child class…

@Service
class Child {
    @Async
    void run() {
        Thread.sleep(500)
        println "Child: ${SecurityContextHolder.context.authentication?.principal}"
    }
}

Let’s also assume the user has successfully logged in and Spring Security has set up the user authentication info.

The Parent will spawn a new thread (through @Async) to run Child.

When invoking the Parent, this is what we see:-

Parent: USER_PRINCIPAL
Parent: Done
Child: null

The Child, for some reason, doesn’t get the receive the user authentication info.

SOLUTION

By default, SecurityContextHolder uses MODE_THREADLOCAL to store the user authentication info. As a result, this info is not accessible to methods outside the current execution thread.

To fix this, configure SecurityContextHolder to use MODE_INHERITABLETHREADLOCAL to pass the user authentication info to other spawned threads.

@Configuration
@EnableAsync
class AppConfig {
    AppConfig() {
        SecurityContextHolder.setStrategyName(SecurityContextHolder.MODE_INHERITABLETHREADLOCAL)
    }
}

When invoking the Parent again, now the Child will also receive the user authentication object:-

Parent: USER_PRINCIPAL
Parent: Done
Child: USER_PRINCIPAL

JEE Security: Preventing Clickjacking Attacks

PROBLEM

Clickjacking is an attack that tricks the users to perform unintended actions… see OWASP’s Testing for Clickjacking (OTG-CLIENT-009)

SOLUTION

To prevent clickjacking attacks, the app must set X-FRAME-OPTIONS header with an appropriate value:-

  • DENY: this denies any domain using the page as an iFrame source. This is the best option.
  • SAMEORIGIN: this allows pages within the same domain to use other application pages as iFrame sources.
  • ALLOW-FROM [whitelisted domains]: this declares a list of domains that are allowed to include the pages as iFrame sources.

If set correctly, the HTTPS response should show X-FRAME-OPTIONS header:-

➜  ~ curl -i -k https://localhost:8443/
HTTP/1.1 200
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Pragma: no-cache
Expires: 0
Strict-Transport-Security: max-age=31536000 ; includeSubDomains
X-Frame-Options: DENY
X-Application-Context: application:local:8443
Set-Cookie: JSESSIONID=04ADDAF886A20AA561021E869E980BCC; Path=/; Secure; HttpOnly
Content-Type: text/html;charset=UTF-8
Content-Language: en-US
Content-Length: 631
Date: Thu, 31 Aug 2017 14:56:57 GMT

There are several ways to set this header.

Solution 1: Using a servlet filter

You may create a servlet filter that sets X-FRAME-OPTIONS in the response header.

Here’s an example using web.xml-less Spring Boot:-

@SpringBootApplication
class Application extends SpringBootServletInitializer {
    static void main(String[] args) {
        SpringApplication.run(Application, args)
    }

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(Application)
    }

    @Bean
    FilterRegistrationBean clickjackingPreventionFilter() {
        return new FilterRegistrationBean(
                urlPatterns: ['/**'],
                filter: new Filter() {
                    @Override
                    void init(final FilterConfig filterConfig) throws ServletException {
                    }

                    @Override
                    void doFilter(final ServletRequest servletRequest,
                                  final ServletResponse servletResponse,
                                  final FilterChain filterChain) throws IOException, ServletException {
                        final HttpServletResponse response = (HttpServletResponse) servletResponse
                        response.addHeader('X-FRAME-OPTIONS', 'DENY')
                        filterChain.doFilter(servletRequest, servletResponse)
                    }

                    @Override
                    void destroy() {
                    }
                }
        )
    }
}

Solution 2: Using Spring Security

Spring Security provides a very easy way to set the X-FRAME-OPTIONS header:-

@Configuration
@EnableWebSecurity
class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(final HttpSecurity http) throws Exception {
        http.
                headers().frameOptions().deny().
                and().
                authorizeRequests().
                antMatchers('/**').permitAll()
    }
}

Spring Security: Invalid CSRF Token ‘null’ was found on the request parameter ‘_csrf’ or header ‘X-CSRF-TOKEN’

PROBLEM

With Spring Security 4.x, the CSRF protection is enabled by default. You may disable it, but to be more aligned with OWASP and the industry security standard, it’s best to leave this setting the way it is. Learn more about CSRF attack…

To prevent this attack, Spring Security 4.x requires you to attach a server-side generated CSRF token on any POST, PUT or DELETE calls… basically, actions that may modify the request state. Their argument for not attaching this token on GET is to prevent this token value from leaking out.

Further, you will require to call POST /login and POST /logout now. In the past, you can call GET /j_spring_security_logout without problem.

If you invoke POST, PUT or DELETE without this CSRF token, you will get a 403 error with this message: “Invalid CSRF Token ‘null’ was found on the request parameter ‘_csrf’ or header ‘X-CSRF-TOKEN’.”.

SOLUTION

To obtain this CSRF token, add this Spring Security custom tag to the JSP file:-

<!DOCTYPE html>
<html>
	<head>
	    <sec:csrfMetaTags/>
	</head>
	<body>
	</body>
</html>

The rendered HTML looks like this:-

<!DOCTYPE html>
<html class="no-js">
	<head>
	    <meta name="_csrf_parameter" content="_csrf" />
	    <meta name="_csrf_header" content="X-CSRF-TOKEN" />
	    <meta name="_csrf" content="e62835df-f1a0-49ea-bce7-bf96f998119c" />
	</head>
	<body>
	</body>
</html>

Finally, set the request header before making the AJAX call:-

var header = $("meta[name='_csrf_header']").attr("content");
var token = $("meta[name='_csrf']").attr("content");

$.ajax({
    url: '/test',
    type: 'POST',
    beforeSend: function(xhr){
        xhr.setRequestHeader(header, token);
    },
    success: function(data) {
        console.log(data);
    },
    error: function (xhr, ajaxOptions, thrownError) {
        console.log(xhr.status + ": " + thrownError);
    }
});