CVE-2023-34035: CVE-2023-34035: Authorization rules can be misconfigured when using multiple servlets

Description

Severity is high unless otherwise noted.

Spring Security versions 5.8 prior to 5.8.5, 6.0 prior to 6.0.5 and 6.1 prior to 6.1.2 could be susceptible to authorization rule misconfiguration if the application uses requestMatchers(String) and multiple servlets, one of them being Spring MVC’s DispatcherServlet.

(DispatcherServlet is a Spring MVC component that maps HTTP endpoints to methods on @Controller-annotated classes.)

Specifically, an application is vulnerable when all of the following are true:

• Spring MVC is on the classpath
• Spring Security is securing more than one servlet in a single application (one of them being Spring MVC’s DispatcherServlet)
• The application uses requestMatchers(String) to refer to endpoints that are not Spring MVC endpoints

An application is not vulnerable if any of the following is true:

• The application does not have Spring MVC on the classpath
• The application secures no servlets other than Spring MVC’s DispatcherServlet
• The application uses requestMatchers(String) only for Spring MVC endpoints

Affected Spring Products and Versions

• Spring Security 5.8.0 to 5.8.4
• Spring Security 6.0.0 to 6.0.4
• Spring Security 6.1.0 to 6.1.1

Mitigation

Users of affected versions should apply the following mitigations.

First:

• 5.8.x users should upgrade to 5.8.5
• 6.0.x users should upgrade to 6.0.5
• 6.1.x users should upgrade to 6.1.2

Second, if you are using multiple servlets and one of them is Spring MVC’s DispatcherServlet, you may see the following error message at startup time:

This method cannot decide whether these patterns are Spring MVC patterns or not.
If this endpoint is a Spring MVC endpoint, please use `requestMatchers(MvcRequestMatcher)`;
otherwise, please use `requestMatchers(AntPathRequestMatcher)`.

Please follow this error message.

For example, if you were using requestMatchers(String) to point to a non-Spring MVC endpoint, /endpoint, then change it to requestMatchers(new AntPathRequestMatcher(“/endpoint”)).

If you were using requestMatchers(String) to point to a Spring MVC endpoint, /mvc-endpoint, then change it to requestMatchers(new MvcRequestMatcher(introspector, “/mvc-endpoint”)) where introspector is an @Autowired HandlerMappingIntrospector.

For an example mitigation, please see the following Spring Security sample application and the corresponding diff.

Credit

This issue was identified and responsibly reported by senior software engineer Mouad Kondah from Kudelski Security.