By now, hijacking laptop cameras is an old hacker trick, but new research dug up by The Washington Post suggests there may be a way to do it without setting off a MacBook's telltale warning light, a feature designed to make sure users know when they're being watched. The story starts with a former FBI agent suggesting that, for years, the bureau has has been covertly activating laptops in order to spy on subjects. That's supposed to be impossible, but Johns Hopkins computer scientist Stephen Checkoway may have figured out how it's done.

The key feature is the iSight camera's micro-controller chip, which establishes a hardware-level interlock between the camera and the indicator light. As long as the chip's working, the light will turn on whenever the camera does — but if you're able to remotely reprogram the chip, as Checkoway does, you can get around the safeguard. Checkoway has produced proof-of-concept software showing it works, but so far, he can only perform the trick on Macbooks released before 2008. There could be a similar vulnerability in modern cameras, the article suggests, but so far no one's been able to make it work on more recent models.