Novel Eavesdropping Attack or The Bright Spy

The usual way of eavesdropping with a glass over the wall has come a long way: bugs in the wall, hacking weak passwords, wiretaps, and more. Now, as if there weren't enough ways of being an audio spy, the good old light bulb has become a nemesis to be feared: Any light bulb in a room that is visible from the window can be used to spy on your conversations from afar.

A team of researchers at the Ben-Gurion University of the Negev in Israel has found that the vibration patterns in a light bulb can enable us to recover full conversations from hundreds of feet away.

But how can that be possible? The thing about the hanging bulb is that it acts both as a diaphragm and transducer. Apparently, these two, sound waves cascading on its surface and it converting air pressure from sound to small changes in light, means it is a useful gadget for intruders.

The paper states, "We show how fluctuations in the air pressure on the surface of the hanging bulb (in response to sound), which cause the bulb to vibrate very slightly (a millidegree vibration), can be exploited by eavesdroppers to recover speech and singing, passively, externally, and in real time." more