Computer hackers can use power sockets to scout what people are typing, warn experts.Researchers Andrea Barisani and Daniele Bianco, of Inverse Path, have revealed that poor shielding on some keyboard cables can allow hackers to identify each character typed on a computer.
According to the BBC, the information passed along cables connecting keyboards to desktop PCs is leaked onto power circuits. “Our goal is to show that information leaks in the most unexpected ways and can be retrieved,” the Daily Telegraph quoted the researchers as saying.
During the study, the research focused on the cables used to connect a type of keyboard, called a PS/2, to desktop PCs. They found that six wires inside a PS/2 cable were typically “close to each other and poorly shielded”, thus information travelling along the data wire, when a key is pressed, leaks onto the earth wire in the same cable. The study said that picking up the voltage changes, which identify each keystroke, was made easier because data travels along PS/2 cables one bit at a time.
A digital oscilloscope was used to gather data about voltage changes on a power line and filters were used to remove those caused by anything other than the keyboard.
“The PS/2 signal square wave is preserved with good quality... and can be decoded back to the original keystroke information”, wrote the pair in a paper. They demonstrated it working over distances of 1, 5, 10 and 15m from a target, far enough to suggest it could work in a hotel or office. The attack is due to be demonstrated at the Black Hat conference that takes place in
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