In my attempt to make my web application secure, I was testing the URL “myapp/resources//etc/passwd” to see if it correctly handles any malicious URL. Although the request itself returns a 404 Http Status code to the browser, I can still see the following error on my log file

org.springframework.security.web.firewall.RequestRejectedException: The request was rejected because the URL contained a potentially malicious String "//"
    at org.springframework.security.web.firewall.StrictHttpFirewall.rejectedBlocklistedUrls(StrictHttpFirewall.java:456)
    at org.springframework.security.web.firewall.StrictHttpFirewall.getFirewalledRequest(StrictHttpFirewall.java:429)
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:196)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:183)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

I tried making a filter to handle this error but it seems that the firewall from spring security would always get to it before any filter.

Ofcourse I don’t want to allow the URL but I also don’t want the application to throw this error.
How do I solve this issue?