Information
Being able to specify different path-delimiters on Tomcat creates the possibility that an attacker can access applications that were previously blocked a proxy like mod_proxy.
Solution
Start Tomcat with ALLOW_BACKSLASH set to false and ALLOW_ENCODED_SLASH set to false. Add the following to your startup script:
-Dorg.apache.catalina.connector.CoyoteAdapter.ALLOW_BACKSLASH=false
-Dorg.apache.tomcat.util.buf.UDecoder.ALLOW_ENCODED_SLASH=false