By monitoring the flashes of LED lights on electronics equipment and the indirect glow from monitors, scientists in the United States and the United Kingdom have discovered ways to remotely eavesdrop on computer data.
Optical signals from the little flashing LED (light-emitting diode) lights, usually red and dotting everything from modems to keyboards and routers, can be captured with a telescope and processed to reveal all the data passing through the device, Joe Loughry, a computer programmer at Lockheed Martin Space Systems in Denver, told Reuters on Wednesday.
"It requires little apparatus, can be done at a considerable distance, and is completely undetectable," he writes in his paper, "Information Leakage from Optical Emanations." "In effect, LED indicators act as little free-space optical data transmitters, like fiber optics but without the fiber."
Not every LED-enabled device is at risk, though. Affected is equipment used in low-speed, long-distance networks typically found in proprietary networks, such as ATM (automated teller machines) at banks, as opposed to corporate local area networks or home Internet connections, Loughry said.
He said he was able to collect a strong optical signal from about 22 yards, using optical sensor equipment.
"It is interesting to walk around downtown at night in a large city and look up at the glass windows and you see a lot of computers," Loughry said. "I've seen racks of equipment with LEDs on them visible from the street. That's kind of what got me to pursue this."
News source: ZDNet News
Additional News source: Slashdot - LED Lights: Friend or Foe?
