Keystrokes Can Be Sniffed Without the PC Being Compromised
By picking up the electromagnetic radiations wired keyboards emit

Two Swiss researchers have demonstrated, in James Bond-like experiments, that sniffing the keystrokes from a wired keyboard is possible by capturing the electromagnetic radiations that are emitted when the keys are pressed. The researchers devised four methods of attack, one of which successfully decodes the pressed keys from a distance up to 20 meters, through an office wall, with a rather simple wireless antenna.

The knowledge that computer systems generate compromising emanations or Tempest radiation is dated back to the 1960s, the military organizations being the first to run tests with it. However, it was believed that modern wired keyboards had been constructed in order to overcome this problem. Martin Vuagnoux and Sylvain Pasini, two researchers from the Security and Cryptography Laboratory at Ecole Polytechnique Federale de Lausanne in Switzerland, set out to prove that many keyboards sold today are still vulnerable to this type of attacks.

One of their attack techniques has been based on a previous more generic research by Markus G. Kuhn and Ross J. Anderson, from the Computer Laboratory at the University of Cambridge. This technique is already known in the security industry as the Kuhn attack. The two Swiss researchers have used in their test 11 different wired keyboards, USB and PS2, external and embedded in laptops, which were bought after 2001. All of the tested keyboards have been found vulnerable to at least one of the four attacks.

The first test involved a very basic antenna constructed from a one-meter long wire and situated close to the keyboard. The keyboard was powered with the help of a laptop running on battery. The AC power source of the laptop has been disconnected and its screen closed in order to prevent any interference. The words “trust no one” have been typed on the keyboard and successfully displayed on another monitor after decoding and filtering the captured electromagnetic emanations from the keyboard.

For more details: Softpedia