Research undertaken between 2008 and 2014 suggests that more than 81% of Tor clients can be ‘de-anonymised’ – their originating IP addresses revealed – by exploiting the ‘Netflow’ technology that Cisco has built into its router protocols, and similar traffic analysis software running by default in the hardware of other manufacturers.
more here.........http://thestack.com/chakravarty-tor-traffic-analysis-141114
more here.........http://thestack.com/chakravarty-tor-traffic-analysis-141114