GCHQ and NSA cyber-spooks secretly report vulnerabilities in Tor so they can be patched, a leading developer of the anonymity-preserving software has claimed.

Andrew Lewman, the Tor Project's executive director, claimed that some spies place a higher priority on fixing flaws in the privacy-preserving technology than keeping secret bugs that might help their colleagues' "dark web" surveillance efforts.

"There are plenty of people in both organisations who can anonymously leak data to us to say - maybe you should look here, maybe you should look at this to fix this," Lewman ‪told‬ the BBC. "And they have."

Systems to submit bugs in Tor are designed to protect the privacy of tipsters so, as Lewman admits, he's unable to prove who sent them in. Lewman explained that his "hunch" that cyberspies are leaking information about bugs and design issues in Tor because of the deep insight implicit in some vulnerability reports.

"You have to think about the type of people who would be able to do this and have the expertise and time to read Tor source code from scratch for hours, for weeks, for months, and find and elucidate these super-subtle bugs or other things that they probably don't get to see in most commercial software," Lewman elaborated.

Both NSA and GCHQ declined to comment on Lewman's suspicions.

TOR blimey

Leaks from whistleblower Edward Snowden revealed that the NSA hoovers up Tor traffic for analysis, as well as constantly looking for vulnerabilities that would allow it to unmask the identities of people using the anonymization technology.

The NSA has directly targeted users of the anonymity network for surveillance. More recently it emerged that someone - circumstantial evidence suggests it was researchers from Carnegie Mellon University – were trying to de-anonymize users of Tor hidden services.

These efforts are far from isolated. Earlier this month it ‪emerged‬ that the FBI was using "drive-by downloads" in an attempt to unmask child abusers that made use of Tor.

Eye-watering

Tor – The Onion Router – was originally developed by the US Naval Research Laboratory. The US State Department continues to provide funding for the technology, which is used by human rights activists, the military and business to preserve their anonymity while surfing the web and accessing online services.

Tor is also used for all manner of unsavoury enterprises, including the sale of illegal drugs, malware distribution, and hosting images of child abuse. It has also been used as a communication channel for everyone from terrorists to spies.

"GCHQ heavily relies on Tor working to be able to do a lot of their operations," according to Lewman. "You can imagine one part of GCHQ is trying to break Tor, the other part is trying to make sure it's not broken because they're relying on it to do their work," he added.

A transcript of Lewman's interview with the BBC can be found ‪here‬.

Tor supports about 2.5 million users a day. Its browser technology has been downloaded 150 million times in the last 12 months.

‪Earlier this week iSec Partners‬ delivered recommendations on Tor Browser hardening, based on a ‪study‬ of the anonymity-protecting technology. ®