abstract: Compartmentalizing access to content, be it websites accessed in a browser or documents and applications accessed outside the browser, is an established method for protecting information integrity [12, 19, 21, 60]. Compartmentalization solutions change the user experience, introduce performance overhead and provide varying degrees of security. Striking a balance between usability and security is not an easy task. If the usability aspects are neglected or sacrificed in favor of more security, the resulting solution would have a hard time being adopted by end-users. The usability is affected by factors including (1) the generality of the solution in supporting various applications, (2) the type of changes required, (3) the performance overhead introduced by the solution, and (4) how much the user experience is preserved. The security is affected by factors including (1) the attack surface of the compartmentalization mechanism, and (2) the security decisions offloaded to the user. This dissertation evaluates existing solutions based on the above factors and presents two novel compartmentalization solutions that are arguably more practical than their existing counterparts. The first solution, called FlexICon, is an attractive alternative in the design space of compartmentalization solutions on the desktop. FlexICon allows for the creation of a large number of containers with small memory footprint and low disk overhead. This is achieved by using lightweight virtualization based on Linux namespaces. FlexICon uses two mechanisms to reduce user mistakes: 1) a trusted file dialog for selecting files for opening and launching it in the appropriate containers, and 2) a secure URL redirection mechanism that detects the user’s intent and opens the URL in the proper container. FlexICon also provides a language to specify the access constraints that should be enforced by various containers. The second solution called Auto-FBI, deals with web-based attacks by creating multiple instances of the browser and providing mechanisms for switching between the browser instances. The prototype implementation for Firefox and Chrome uses system call interposition to control the browser’s network access. Auto-FBI can be ported to other platforms easily due to simple design and the ubiquity of system call interposition methods on all major desktop platforms. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2018

The growth of web-based malware and phishing attacks has catalyzed significant advances in the research and use of interstitial warning pages and modals by a browser prior to loading the content of a suspect site. These warnings commonly use visual cues to attract users' attention, including specialized iconography, color, and an absence of buttons to communicate the importance of the scenario. While the efficacy of visual techniques has improved safety for sighted users, these techniques are unsuitable for blind and visually impaired users. This is likely not due to a lack of interest or technical capability by browser manufactures, where universal design is a core tenet of their engineering practices, but instead a reflection of the very real dearth of research literature to inform best practices, exacerbated by a deficit of clear methodologies for conducting studies with this population. Indeed, the challenges are manifold. In this paper, we present the results of our study analyzing the experiences of the visually impaired with browser security warnings, detail the development and advancement of the methodological best practices when conducting a study of this kind, and ultimately identify some initial approaches that could improve the security for this population.

Modern web applications use several third-party JavaScript libraries to achieve higher levels of engagement. The third-party libraries range from utility libraries such as jQuery to libraries that provide services such as Google Analytics and context- sensitive advertisement. These third-party libraries have access to most (if not all) the elements of the displayed webpage. This allows malicious third-party libraries to perform attacks that steal information from the end-user or perform an action without the end-user consent. These types of attacks are the stealthiest and the hardest to defend against, because they are agnostic to the browser type and platform of the end-user and at the same time they rely on web standards when performing the attacks. Such kind of attacks can perform actions using the victim’s browser without her permission. The nature of such actions can range from posting an embarrassing message on the victim’s behalf over her social network account, to performing online biding using the victim’s account. This poses the need to develop effective mechanisms for protecting against client-side web attacks that mainly target the end-user. In the proposed research, we address the above challenges from information flow monitoring perspective by developing a framework that restricts the flow of information on the client-side to legitimate channels. The proposed model tracks sensitive information flow in the JavaScript code and prevents information leakage from happening. The main component of the framework is a hybrid flow-sensitive security monitor that controls, at runtime, the dissemination of information flow and its inlining. The security monitor is hybrid as it combines both static analysis and runtime monitoring of the running JavaScript program. We provide the soundness proof of the model with respect to termination-insensitive non-interference security policy and develop a new security benchmark to establish experimentally its effectiveness in detecting and preventing illicit information flow. When applied to the context of client-side web-based attacks, the proposed model provides a more secure browsing environment for the end-user. / Graduate

The purpose of this thesis is to prevent websites located in public internet from accessing user's internal network through web browser. Acquired knowdledge about modern browser's security mechanism - same-origin policy and options of implementing the web browser extensions using WebExtensions, was used in the solution. Proposed solution is based on WebRequest API, which intercepts and modifies HTTP requests, and extends functionality of existing browser extension JavaScript Restrictor with the ability to detect and prevent the browser to be abused as a proxy for scanning and accessing user's internal network. The implemented solution was tested and accepted as a part of JavaScript Restrictor. The main benefit of this thesis is the protection from possible abusement of a web browser as a proxy, which is not present in existing extensions.