Encoded Precent(%25) with Spring RequestMapping path param gives HTTP 400

Question

I created a controller to do the data search. But when I die with the keyword '%' it returns an HTTP 400 error. Here is the Contrller:

@RequestMapping(value = "/search/{txtKeyWord}")
public String pageVipStory(@PathVariable("txtKeyWord") String txtKeyWord, Model model) {
     logger.info("Keyword In URL: " + txtKeyWord);
     model.addAttribute("txtKeyWord", txtKeyWord);
     model.addAttribute("txtKeyWordEndCode", UriUtils.encode(txtKeyWord, "UTF-8"));
     getMenuAndInfo(model, "Search " + txtKeyWord);

     return "web/searchPage";
}

With the link: "http://localhost:8080/search/%25", the error message:

org.springframework.security.web.firewall.RequestRejectedException: The request was rejected because the URL contained a potentially malicious String "%25" at org.springframework.security.web.firewall.StrictHttpFirewall.rejectedBlacklistedUrls(StrictHttpFirewall.java:325) ~[spring-security-web-5.1.1.RELEASE.jar:5.1.1.RELEASE] at org.springframework.security.web.firewall.StrictHttpFirewall.getFirewalledRequest(StrictHttpFirewall.java:293) ~[spring-security-web-5.1.1.RELEASE.jar:5.1.1.RELEASE] at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:194) ~[spring-security-web-5.1.1.RELEASE.jar:5.1.1.RELEASE] at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) ~[spring-security-web-5.1.1.RELEASE.jar:5.1.1.RELEASE] at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:154) ~[spring-boot-actuator-2.1.0.BUILD-20181030.063958-621.jar:2.1.0.BUILD-SNAPSHOT] at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:122) ~[spring-boot-actuator-2.1.0.BUILD-20181030.063958-621.jar:2.1.0.BUILD-SNAPSHOT] at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:107) ~[spring-boot-actuator-2.1.0.BUILD-20181030.063958-621.jar:2.1.0.BUILD-SNAPSHOT] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.2.RELEASE.jar:5.1.2.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:770) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415) [tomcat-embed-core-9.0.12.jar:9.0.12] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.12.jar:9.0.12] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_172] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_172] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.12.jar:9.0.12] at java.lang.Thread.run(Thread.java:748) [na:1.8.0_172]

Who can show me where the error. And how to overcome it? Thanks!

Answer 1

You can take the default Spring Security Firewall using your custom defined instance of StrictHttpFirewall.

@Bean
public HttpFirewall allowUrlEncodedPercentHttpFirewall() {
    StrictHttpFirewall firewall = new StrictHttpFirewall();
    firewall.setAllowUrlEncodedPercent(true);
    return firewall;
}

Attention that, this can lead to exploits that involve double URL encoding that lead to bypassing security constraints.