Apache Tomcat prior to 5.5.35, 6.x prior to 6.0.35, and 7.x prior to 7.0.23 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote malicious users to cause a denial of service (CPU consumption) by sending many crafted parameters.
This module uses a denial-of-service (DoS) condition appearing in a variety of programming languages. This vulnerability occurs when storing multiple values in a hash table and all values have the same hash value. This can cause a web server parsing the POST parameters issued with a request into a hash table to consume hours of CPU with a single HTTP request. Currently, only the hash functions for PHP and Java are implemented. This module was tested with PHP + httpd, Tomcat, Glassfish and Geronimo. It also generates a random payload to bypass some IDS signatures.
msf > use auxiliary/dos/http/hashcollision_dos msf auxiliary(hashcollision_dos) > show actions ...actions... msf auxiliary(hashcollision_dos) > set ACTION <action-name> msf auxiliary(hashcollision_dos) > show options ...show and set options... msf auxiliary(hashcollision_dos) > run