A security researcher conducted an experiment to demonstrate that someone is sniffing passing traffic from Tor network exit nodes. The researcher found 16 instances of multiple uses of unique passwords, meaning that someone was sniffing the traffic. Roger Dingledine, the co-founder of the Tor project told to the SCMagazineUK.com that he is in communication with Chloe. He disputed the number of suspect exit nodes discovered, saying it was seven rather than 15 or 16, but even so he wasnt surprised or overly concerned about it.”]
Source: http://securityaffairs.co/wordpress/38397/hacking/sniffing-traffic-tor-traffic.html