The talk is about abusing and exploiting Firefox add-on Security model and explains how JavaScript functions, XPCOM and XPConnect interfaces, technologies like CORS and WebSocket, Session storing and f privilege execution can be abused by a hacker for malicious purposes.The widely popular browser add-ons can be targeted by hackers to implement new malicious attack vectors resulting in confidential data theft and full system compromise. This paper is supported by proof of concept add-ons which abuse and exploits the add-on coding in Firefox 18, the release which Mozilla boasts to have a more secure architecture against malicious plugins and add-ons. The proof of concept includes the implementation of a Local keylogger, a Remote keylogger, stealing Linux password files, spawning a Reverse Shell, stealing the authenticated Firefox session data, and Remote DDoS attack. All of these attack vectors are fully undetectable against anti-virus solutions and can bypass protection mechanisms.