Researchers at the KTH Royal Institute of Technology, Stockholm, and Princeton University in the USA have unveiled a new way to attack Tor and deanonymise its users. Tor works by routing your traffic through a randomly chosen circuit of three nodes chosen from about 7000 computers that are offered up for the purpose by volunteers around the world. The entry guard knows where your traffic comes from, but not who you are or whats in it. The last computer in the circuit is drawn from a pool of 1000 out of 7000, known as exit nodes”]
Source: https://nakedsecurity.sophos.com/2016/10/05/unmasking-tor-users-with-dns/