Ruby on Rails JSON Processor YAML Deserialization Code Execution

This Metasploit module exploits a remote code execution vulnerability in the JSON request processor of the Ruby on Rails application framework. This vulnerability allows an attacker to instantiate a remote object, which in turn can be used to execute any ruby code remotely in the context of the application. This vulnerability is very similar to CVE-2013-0156. This Metasploit module has been tested successfully on RoR 3.0.9, 3.0.19, and 2.3.15. The technique used by this module requires the target to be running a fairly recent version of Ruby 1.9 (since 2011 or so). Applications using Ruby 1.8 may still be exploitable using the init_with() method, but this has not been demonstrated.