How to use electrical outlets and cheap lasers to steal data




"The only thing you need for successful attacks are either the electrical grid or a distant line of sight, no expensive piece of equipment is required," Barisani and Bianco say in a paper describing the hacks.

The equipment to carry out the power-line attack could cost as little as $US500, and the laser attack gear costs about $US100 if the attacker already owns a laptop with a sound card, says Barisani. Carrying out the attacks took about a week, he says."We think it is important to raise the awareness about these unconventional attacks and we hope to see more work on this topic in the future," Barisani and Bianco say in their paper. Others with more time and money could doubtless create better spying tools using the same concepts, they say.


Attackers extend the ground of a nearby power socket and attach to it two probes separated by a resistor. The voltage difference and the fluctuations in that difference - the keyboard signals - are captured from both ends of the resistor and converted to letters (see diagram).

To pull the signal out of the ground noise, a reference ground is needed, they say. "A "reference" ground is any piece of metal with a direct physical connection to the Earth, a sink or toilet pipe is perfect for this purpose (while albeit not very classy) and easily reachable (especially if you are performing the attack from [a] hotel room," they say in their paper.Since keyboards and mice signals are in the 1 to 20 kHz range, a filter can isolate that range for listening, they say.

Variations in individual keyboards and mice result in each keyboard signaling in a slightly different frequency range. With careful filtering, that makes it possible to zero in on a particular keyboard in an environment where many keyboards are in use, the researchers say.

The attack proved successful when tapping electric sockets located up to 15 meters from where the target computer was plugged in the researchers say.

This method would not work if the computer were unplugged from the wall, such as a laptop running on its battery. The second attack can prove effective in this case, Bianco's and Barisani's paper says.


This modulation is converted to an electrical signal that is fed into a computer soundcard. "The vibration patterns received by the device clearly show the separate keystrokes," the researchers' paper says. Each key has a unique vibration pattern that distinguishes it from the rest. The spacebar creates a significantly different set of vibrations, so the breaks between words are readily apparent.



Anyone worried about this type of attack can make sure there is no line of sight to the laptop, move position frequently while typing and polluting the signal by striking random keys and later deleting them with the backspace key.

While they admit their hacking tools are rudimentary, they believe they could be improved upon with a little time, effort and backing.

"If our small research was able to accomplish acceptable results in a brief development time (approximately a week of work) and with cheap hardware," they say. "Consider what a dedicated team or government agency can accomplish with more expensive equipment and effort,"

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