The fact that feds have seized Silk Road 2.0 and a bunch of other shady websites hiding behind Tor's technology proves that the browser doesn't provide the perfect cloak of anonymity. Now, a series of studies conducted between 2008 and 2014 gives us a clearer idea of just how vulnerable the browser is. The researchers involved claim to have de-anonymized the IP addresses of all Tor users in a lab setting -- and over 81 percent of actual users in the wild. According to one of the papers published by Sambuddho Chakravarty, former researcher at Columbia University's Network Security Lab, he and his colleagues managed to get through Tor's defenses by exploiting the default traffic analysis software built into routers. In Cisco routers, for instance, it's a program called Netflow.