Recently, however, a new method has been devised and demonstrated by a joint research effort that combined the talents of team members from Michigan State University and Nanjing University in China. Their new method does not require the hacker to create anything new or exotic, but rather, to simply gain control over a router.
Wireless routers track and monitor the signals on your network, including signals sent by your wireless peripherals. If you’re using a wireless keyboard, each time you press a key, it sends a signal of a slightly different wavelength to the CPU, which translates that signal, and displays the appropriate letter or symbol on your screen.
The research team was able to reverse engineer an algorithm that could identify which keystrokes generated what frequencies, and use it to provide a map of every keystroke entered. Their first try yielded a result of better than 96% accuracy. No doubt, with additional refinement, this percentage could be pushed even closer to 100% than it already is.
The only real downside of their method is the fact that the range is fairly limited. If the router is more than 12 to 15 feet from the keyboard in question, accuracy falls off markedly, but this could also change with further refinement, and as routers themselves become more powerful and robust.
The bottom line is that researchers have now demonstrated a method of keystroke capturing which relies on traditional hacking targets (routers), and requires no specialized, custom-built equipment to pull off. Not a month goes by that some new, innovative hacking technique is brought to light, and a new threat is found to guard against. This is yet another of those.