http://booksbxfx6ciebutmfvorkotgfbwcwp24qpcxyuyen355z4eknxbzuqd.onion/dark/Laden_Kash_-_The_Dark_Web_%C2%B7_Exploration_Of_The_Deep_Web/THE_DARK_WEB_2.html
This is despite having cracked the firefox browser add on at one point to access users computers. The Tor browser was subsequently updated and fixed by the coders leading to the following confession from the NSA: Leaked report titled 'Tor Stinks' - “We will never be able to de-anonymize all Tor users all the time.”