An Optical Spy Trick Can Turn Any Shiny Object Into a Bug

The most paranoid among us already know the checklist to avoid modern audio eavesdropping: Sweep your home or office for bugs. Put your phone in a Faraday bag--or a fridge. Consider even stripping internal microphones from your devices. Now one group of researchers offers a surprising addition to that list: Remove every lightweight, metallic object from the room that's visible from a window. At the Black Hat Asia hacker conference in Singapore in May, researchers from Israel's Ben Gurion University of the Negev plan to present a new surveillance technique, designed to allow anyone with off-the-shelf equipment to eavesdrop on conversations if they can merely find a line of sight through a window to any of a wide variety of reflective objects in a given room. By pointing an optical sensor attached to a telescope at one of those shiny objects--the researchers tested their technique with everything from an aluminum trash can to a metallic Rubik's cube--they could detect visible vibrations on an object's surface that allowed them to derive sounds and thus listen to speech inside the room.