NSA using Firefox flaw to snoop on Tor users

An NSA presentation released by Edward Snowden contains mixed news for Tor users. The anonymizing service itself appears to have foxed US and UK government snoops, but instead they are using a zero-day flaw in the Firefox browser bundled with Tor to track users.

"These documents give Tor a huge pat on the back," security guru Bruce Schneier told The Register. "If I was a Tor developer, I'd be really smiling after reading this stuff."

The PowerPoint slide deck, prepared in June last year and entitled "Tor stinks", details how the NSA and the UK's Government Communications Headquarters (GCHQ) have been stymied by trying to track Tor users, thanks to the strength of the open source system.

"We will never be able to de-anonymize all Tor users all the time," the presentation states. "With manual analysis we can de-anonymize a very small fraction of Tor users, however, no success de-anonymizing a user."

The presentation says that both the NSA and GCHQ run Tor nodes themselves (the Brits use Amazon Web Services for this under a project entitled Newton's Cradle), but these are only a very small number in comparison to the whole system. This makes tracking users using traditional signals-intelligence methods impossible.

The agencies have also tried to use "quantum" cookies to track targets who are using Tor.

Source: http://www.theregister.co.uk/2013/10/04/nsa_using_firefox_flaw_to_snoop_on_tor_users/