De-anonymisation attacks on Tor: A Survey

TL;DR

This survey reviews known de-anonymisation attacks on the Tor network, analyzing their techniques, practicality, and discussing potential improvements to enhance user and service anonymity.

Contribution

It provides a comprehensive overview of existing Tor de-anonymisation methods and evaluates their effectiveness and practicality, highlighting areas for future security enhancements.

Findings

Several de-anonymisation techniques are effective against Tor.

Practicality of attacks varies based on resources and conditions.

Improvements to Tor can mitigate many identified attacks.

Abstract

Anonymity networks are becoming increasingly popular in today's online world as more users attempt to safeguard their online privacy. Tor is currently the most popular anonymity network in use and provides anonymity to both users and services (hidden services). However, the anonymity provided by Tor is also being misused in various ways. Hosting illegal sites for selling drugs, hosting command and control servers for botnets, and distributing censored content are but a few such examples. As a result, various parties, including governments and law enforcement agencies, are interested in attacks that assist in de-anonymising the Tor network, disrupting its operations, and bypassing its censorship circumvention mechanisms. In this survey paper, we review known Tor attacks and identify current techniques for the de-anonymisation of Tor users and hidden services. We discuss these techniques and analyse the practicality of their execution method. We conclude by discussing improvements to the Tor framework that help prevent the surveyed de-anonymisation attacks.