Then, finally, the latest scoops in The Guardian and The Washington Post on Friday answered a lot of questions about the NSA and Tor. NSA documents provided by Snowden reveal many different attempts and strategies (some of them successful) to attack Tor users. The slideshow is called “The Tor Problem,” helpfully explaining that Tor is a big, big problem, because terrorism.) Emphasizing Andrew Lewman’s point from above, the documents demonstrate that the NSA has been trying to crack Tor since 2006, even though other government agencies—such as the State Department—have been funding it and actively promoting it as a tool of democracy and liberation for people living under dictatorship rule.
These latest files show that the NSA has been able to, for instance, spot a random Tor user, attack that person’s computer via vulnerable browser software, and then, through those attacks, monitor his or her online activities. One proposed technique turns out to be the same one that the Chinese government uses to block its citizens from accessing the censored Internet there.
However, according to these new documents, the NSA has not been able to target a specific person for a cyberattack. It also hasn’t figured out how to generalize this method in order to perform any kind of mass-Tor-surveillance. And, significantly, these revelations don’t hint at any new vulnerability in the overall Tor network itself—which seemed like a relief to the privacy experts interviewed by the Guardian and the Post. A lot of other attacks and attempts appear to be hypothetical or to have failed. (Technical details are available here, courtesy of longtime encryption master Bruce Schneier.)
Incidentally, yet another technique that the documents describe is the very same one that the FBI used this summer to take down Freedom
HouseHosting, which had provided hosting for the hidden services on Tor and had become associated with child porn. (Tor took pains to stress that Freedom HouseHosting was not affiliated with Tor, and that, again, the shutdown didn’t mean anything in particular for the security of Tor overall.) That particular episode, unlike the Silk Road bust, didn’t get much attention in the press. (Was it because host providers are less interesting than online marketplaces, or because child porn is an ickier topic than drugs? Unclear.)
In any case, the staff and volunteers at The Tor Project remain confident in the security of the system, despite, and in fact because of, these new revelations. The latest document drop has revealed just how little progress the NSA has actually made in its battle against Tor, while allowing Tor to patch whatever small breaches in the system the NSA has found. Above all, Tor’s Roger Dingledine once again reminded readers, Tor’s greatest asset is its transparency. “Tor still helps here: you can target individuals with browser exploits, but if you attack too many users, somebody’s going to notice,” wrote Dingledine in a statement he sent to The Guardian and posted on the Tor blog Friday. “So even if the NSA aims to surveil everyone, everywhere, they have to be a lot more selective about which Tor users they spy on.”
In the comments below that post, Dingledine also mentioned that at least one of the NSA documents appeared to be the work of a couple of college-aged interns, and did not necessarily represent NSA’s “master plan.” Good point. The presentation uses language like “Tor stinks,” and one slide features a ludicrous cartoon of “terrorist with Tor client installed”—he’s got a gun, he’s got a beard, and he’s wearing a bandit mask. And he’s apparently browsing the internet. Oh, and his desk chair is a giant onion.