A claimed zero-day vulnerability in Firefox 17 was used by the FBI to identify some users of the privacy-protecting Tor anonymity network. The FBI did not compromise the TOR network itself and The complex multi-layers of encryption still stand. Eric Eoin Marques, 28 year-old man in Ireland believed to be behind Freedom Hosting, the biggest service provider for sites on the encrypted Tor network, is awaiting extradition on p*rno charges. His arrest coincides with mass outages across the Darknet affecting popular services like Tor Mail, HackBB and the Hidden Wiki.
Source: https://thehackernews.com/2013/08/Firefox-Exploit-Tor-Network-child-pornography-Freedom-Hosting.html