Battal, Mustafa2016-01-082016-01-082014http://hdl.handle.net/11693/16901Ankara : The Department of Computer Engineering and the Graduate School of Engineering and Science of Bilkent University, 2014.Thesis (Master's) -- Bilkent University, 2014.Includes bibliographical references leaves 41-44.A poorly designed web browser extension with a security vulnerability may expose the whole system to an attacker. Therefore, attacks directed at “benign-butbuggy” extensions, as well as extensions that have been written with malicious intents pose significant security threats to a system running such components. Recent studies have indeed shown that many Firefox extensions are over-privileged, making them attractive attack targets. Unfortunately, users currently do not have many options when it comes to protecting themselves from extensions that may potentially be malicious. Once installed and executed, the extension needs to be trusted. This thesis introduces Sentinel, a policy enforcer for the Firefox browser that gives fine-grained control to the user over the actions of existing JavaScript Firefox extensions. The user is able to define policies (or use predefined ones) and block common attacks such as data exfiltration, remote code execution, saved password theft, and preference modification. Our evaluation of Sentinel shows that our prototype implementation can effectively prevent concrete, real-world Firefox extension attacks without a detrimental impact on users’ browsing experience.ix, 52 leaves, graphicsEnglishinfo:eu-repo/semantics/openAccessWeb browser securityBrowser extensionsQA76.9.A25 B38 2014Computer security.World Wide Web (Information retrieval system)--Security measures.ThesisB149307