Security seminar: "Winning the Censorship Arms Race"

25 Feb
Thursday, 02/25/2016 2:00pm to 3:00pm
Computer Science Building, Room 151
Speaker: Phillipa Gill

The Internet has become a critical communication infrastructure for citizens to obtain accurate information, organize political actions, and express dissatisfaction with their governments. This fact has not gone unnoticed, with governments clamping down on this medium via censorship, surveillance and even large-scale Internet take-downs. As online information controls become more common, circumvention researchers are left working tirelessly to stay one step ahead. In this talk, I will present my research which leverages network measurement as a basis to stay one step ahead in the censorship arms race. First, I will present our characterization of attacks that correlate traffic entering and exiting the Tor anonymity system to deanonymize users. This characterization is the first to tackle the challenge of estimating the presence of adversaries on both forward and reverse network paths using empirical data. Our analysis shows that more than half of the time Tor builds a circuit that is vulnerable to these attacks.  I will then discuss Astoria, a system that uses knowledge of network paths to build circuits that avoid traffic correlation attacks, effectively reducing the number of vulnerable circuits by 4X. In the second half of the talk, I will present our work measuring specifically which products are being used for censorship. While these products were originally designed to improve performance and protect users from inappropriate content, they are also used to censor Web content by authoritarian regimes around the globe. Using a combination of measurements by individuals in the field, and a novel experiment methodology we were able to identify two North American products being used by ISPs in Saudi Arabia, United Arab Emirates (UAE), Qatar and Yemen to block content protected in the UN Declaration of Human Rights. Finally, I will discuss my broad research agenda, which includes tackling a variety of issues ranging from measuring and modeling the behaviors of censors to understanding traffic manipulations more broadly (e.g., those implemented by middle boxes in mobile networks, or by ISPs violating network neutrality).

Bio:  Phillipa Gill is an assistant professor in the Computer Science Department at Stony Brook University. Her work focuses on many aspects of computer networking and security with a focus on designing novel network measurement techniques to understand online information controls, network interference, and interdomain routing. She currently leads the ICLab project which is working to develop a network measurement platform specifically for online information controls. She has received the NSF CAREER award, Google Faculty Research Award and best paper awards at the ACM Internet Measurement Conference (characterizing online aggregators), and Passive and Active Measurement Conference (characterizing interconnectivity of large content providers).



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