Professors at the University of Luxembourg explain how the TOR Network is not secure

Technology professors at the University of Luxembourg have released a document detailing the vulnerabilities of the TOR network entitled: Trawling for Hidden Services: Detection, Measurement, Deanonymization. In short, the 15 page report, written by Alex Biryukov, Ivan Pustogarov, and Ralf-Philipp Weinmann, explains how attackers can uncover an individual’s IP address by controlling one or more of the TOR relay points. From there the attacker can use primitive traffic analysis to identify the users on that relay or any of its connectors. The paper concludes that attacks to deanonymize hidden services at a large scale are practically possible with only a moderate amount of resources, although it may take up to 2 days to do so.  

Trawling for Hidden Services: Detection, Measurement, Deanonymization