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

Technological advancements have transformed the way people interact with the world. The Internet now forms a critical infrastructure that links different aspects of our life like personal communication, business transactions, social networking, and advertising. In order to cater to this ever increasing communication overhead there has been a fundamental shift in the network infrastructure. Modern network routers often employ software programmable network processors instead of ASIC-based technology for higher throughput performance and adaptability to changing resource requirements. This programmability makes networking infrastructure vulnerable to new class of network attacks by compromising the software on network processors. This issue has resulted in the need for security systems which can monitor the behavior of network processors at run time. This thesis describes an FPGA-based security monitoring system for multi-core network processors. The implemented security monitor improves upon previous hardware monitoring schemes. We demonstrate a state machine based hardware programmable monitor which can track program execution flow at run time. Applications are analyzed offline and a hash of the instructions is generated to form a state machine sequence. If the state machine deviates from expected behavior, an error flag is raised, forcing a network processor reset. For testing purposes, the monitoring logic along with the multi-core network processor system is implemented in FPGA logic. In this research, we modify the network processor memory architecture to improve security monitor functionality. The efficiency of this approach is validated using a diverse set of network benchmarks. Experiments are performed on the prototype system using known network attacks to test the performance of the monitoring subsystem. Experimental results demonstrate that out security monitor approach provides an efficient monitoring system in detecting and recovering from network attacks with minimum overhead while maintaining line rate packet forwarding. Additionally, our monitor is capable of defending against attacks on processor with a Harvard architecture, the dominant contemporary network processor organization. We demonstrate that our monitor architecture provides no network slowdown in the absence of an attack and provides the capability to drop packets without otherwise affecting regular network traffic when an attack occurs.

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