Presenters at the CanSecWest security conference detailed how to sniff data by analyzing keystroke vibrations using a laser pointed at a laptop computer, or through electrical signals coming from a PS/2 keyboard on a PC plugged into an electrical socket.
Using about $80 worth of equipment, researchers from Inverse Path pointed a laser on the reflective surface of a laptop between 50 feet and 100 feet away and were able to determine what letters were typed. Line-of-sight is required, but it works through a glass window. Using an infrared laser would prevent the victim from discovering they are under surveillance.
In the second attack method, researchers were able to determine keystrokes on a PS/2 keyboard through a ground line from a power plug in an outlet 50 feet away. They used a digital oscilloscope and analog-digital converter, as well as filtering technology to isolate the keystroke pulses from other power line noise.
