A Framework for MIME Type Identification and Content Filtering in the Firefox Web Browser

Open Access
Rummel, Matthew James
Graduate Program:
Computer Science and Engineering
Master of Science
Document Type:
Master Thesis
Date of Defense:
November 09, 2012
Committee Members:
  • Patrick Drew Mcdaniel, Thesis Advisor
  • Web browser security
Modern Web browser architectures allow for extensibility in order to support an evolving variety of content. Each supported plugin interacts with the browser and underlying host through a diverse set of operations that bring new challenges to the security model. These capabilities provide the means for a growing number of attack vectors that leverage the lax MIME type verification utilities in browsers to disguise malicious files. Once loaded by a browser, these objects take advantage of the escalated privileges available to their concealed payload in order to execute commands on the client. Such attacks can be launched from files shared on social media sites, through email, or from a server controlled by the attacker. To protect against these threats, we offer MIME Detector, a Firefox browser extension to identify and monitor the browser's use of loading objects. By utilizing a collection of open source tools and internal browser components, the tool is able to determine the MIME type of incoming content and enforce an acceptable use policy. Our testing shows that this research provides a solid framework towards providing users with a greater level of control over how Web based content interacts with their client.