You can steal data from a computer using its fan

Israeli researchers have managed to recover data from a computer that is physically isolated from any network. Their AiR-ViBeR technique consists in imperceptibly changing the speed of the PC’s internal fan in order to transmit information in the form of vibrations.

The air gap consists of physically isolating a computer from the local network and the Internet . This makes it possible to protect the most critical workstations, such as in a nuclear power plant , or to secure highly sensitive data. This technique is not without flaws , as researchers from the Ben-Gurion University of the Negev in Israel have demonstrated.

The team developed a technique called AiR-ViBeR to bypass the air gap protection  . It uses the fan of an isolated computer to send information invisibly to a smartphone on site. The research is led by Mordechai Guri, who has already discovered other techniques for transmitting data from a computer disconnected from the network, for example by modulating the brightness of the screen .

Malware is required

AiR-ViBeR works by modulating the fan speed in order to encode data. This technique creates vibrations which cross the desk on which the PC is placed , and which can be detected by the accelerometer of a smartphone placed on the same surface. The transmission data is relatively slow, since researchers reached a maximum speed of a half bit per second, or 16 seconds to a single byte .

One of the main limitations of this technique is the need to install malware on the isolated PC , which implies physical access or enticing a victim to use an infected USB key . In addition, the smartphone must be equipped with a special application to decode the vibrations. However, since access to the accelerometer does not require any special authorization request, malware could more easily go unnoticed. AiR-ViBeR, however, is unlikely to be really used one day, given its slowness.