A new global security threat has emerged after researchers in Europe found that power sockets can be tapped into to identify what people type on a computer.
According to researcher at security Company Inverse Path, poor shielding on some keyboard cables means data can be leaked about each character typed. By analysing the information leaking onto power circuits, the researchers could see what a target was typing.
In a white paper obtained by ChannelNews the researchers say “In the late 60’s and early 70’s the term, Tempest was coined to title an NSA operation which aimed to secure electronic equipment from leakage of compromising emanations. The research describes remote eavesdropping of CRT displays and most recently LCD displays, as well as optical emanations from appliances LED indicators”.
(See attached research paper) which will be presented at a live security demonstration in Las Vegas later this month.
Inverse Path details two attacks, one against wired PS/2 keyboards, the other against laptop keyboards using respectively power line leakage and optical sampling of mechanical energy.
In the Las Vegas demonstration the researchers say that they will show how using relatively cheap homemade hardware they can implement basic but powerful techniques for remotely eavesdropping keystrokes.
“The two presented attacks partially build upon existing concepts and techniques, but while some of the ideas might have been publicly hinted, no clear analysis and demonstration has ever been presented as far as we know”. Andrea Barisani and Daniele Bianco, of security firm Inverse Path wrote.
The researchers revealed that data travels along PS/2 cables one bit at a time and uses a clock speed far lower than any other PC component. Both these qualities make it easy to pick out voltage changes caused by key presses.
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 the paper describing their work.
They demonstrated it working over distances of 1, 5, and 10 and 15m from a target, far enough to suggest it could work in a hotel or office.
