Security researchers tonight are poring over a piece of malicious software that takes advantage of a Firefox security vulnerability to identify some users of the privacy-protecting Tor anonymity network.
The malware showed up Sunday morning on multiple websites hosted by the anonymous hosting company Freedom Hosting. That would normally be considered a blatantly criminal "drive-by" hack attack, but nobody's calling in the FBI this time. The FBI is the prime suspect.
"It just sends identifying information to some IP in Reston, Virginia," says reverse-engineer Vlad Tsrklevich. "It's pretty clear that it's FBI or it's some other law enforcement agency that's U.S.-based."
If Tsrklevich and other researchers are right, the code is likely the first sample captured in the wild of the FBI's "computer and internet protocol address verifier," or CIPAV, the law enforcement spyware first reported by WIRED in 2007.