This Metasploit module exploits a vulnerability found on Firefox 17.0.6, specifically an use after free of a DocumentViewerImpl object, triggered via an specially crafted web page using onreadystatechange events and the window.stop() API, as exploited in the wild on 2013 August to target Tor Browser users.
e39e25d6845ff273ea20decb29f0fdfaca25648ab187f57278e8c2b631ce94c2