Exploring the Threats Posed by Botnets on Onion-Routing; Internet Anonymity Systems: A Tool for Negotiating Privacy in the United States

Fabrizio, Justin, School of Engineering and Applied Science, University of Virginia
Graham, Daniel, EN-Comp Science Dept, University of Virginia
Ferguson, Sean, EN-Engineering and Society, University of Virginia

Internet usage has skyrocketed over the past two decades, and so has internet data
collection. Internet anonymity systems like Tor Browser provide a means for people of all walks
of life to maintain a level of data privacy while using the internet. As such, these systems have
become a focal point for many aspects of the internet, from legislation to innovation. The
following theses will touch on both the societal effects of the presence of internet anonymity
systems as well as the technical strengths and weaknesses of modern internet anonymity
The STS thesis explored internet anonymity systems through the lens of sociotechnical
imaginaries, dividing the imaginaries surrounding these systems into two groups: those of their
implementers and those of their users. The increasing popularity and steady government funding
of Tor Browser suggests the prevalence of pro-data privacy values in both imaginaries; however,
government surveillance programs, among other evidence, indicates conflict between these two
imaginaries. In this way, internet anonymity systems have become a tool for negotiating privacy
and power between these two groups.
The technical thesis proposes a deanonymizing attack on Tor Browser through the use of
botnets. The proposed attack involves hosting Tor relays on large botnets as a means of
conducting a traffic correlation analysis attack. Since hosting a Tor relay is a voluntary process
with little regulation, a botnet could feasibly account for a very large portion of the Tor network
by hosting relays on every member machine. This would give a single entity access to the
majority of traffic in the Tor network. Using these traffic logs, one could potentially
deanonymize Tor users by correlating the inbound traffic with the outbound traffic, effectively
bypassing the layered encryption by linking the identities of senders with their corresponding
unencrypted traffic. A proposed solution to this would be to modify Tor’s path construction
protocol to incorporate each relay’s “published” field, which records the date and time of
activation, and only construct paths through the network that have a high time difference
between the start and end relays.
Internet anonymity systems proved to be a difficult topic to research from a
sociotechnical standpoint as their decentralized nature made it difficult to identify key
stakeholders; however, the research ended up providing valuable results for both theses. The STS
research clarified Tor Browser’s position as a pivotal technology between two competing
imaginaries while the technical research gave an in-depth assessment of a current weakness of
Tor Browser and proposed a possible solution. On the STS side, future research should expand in
scope to include internet anonymity systems that are not open-source, as the implementers’
imaginaries of for-profit systems will likely contain different values than those of Tor Browser,
while still interacting with the same users’ imaginary. In terms of technical research, validation
of the proposed designs via testing would be valuable in supporting the technical thesis. The
open-source nature of Tor Browser would make testing the modifications described in the thesis
a relatively straightforward process on a closed network.

BS (Bachelor of Science)
sociotechnical imaginaries, onion routing, computer networks

School of Engineering and Applied Science
Bachelor of Science in Computer Science
Technical Advisor: Daniel Graham
STS Advisor: Sean Ferguson
Technical Team Members: Justin Fabrizio

Issued Date: