Researchers use USB drive to send data with radio waves

Researchers from Israel’s Ben Gurion University have developed software that allows them to use an ordinary USB drive as a radio transmitter. According to them, the technology called ‘USBee’ can be used to extract data from air gapped computers.

The scientists write in their research that there have been similar ideas before. For example, the American NSA developed a USB drive with a built-in radio transmitter for the same purpose under the name ‘Cottonmouth’. However, the Israeli researchers’ technique uses a standard USB drive in combination with the USBee software. By sending a series of 0-bits to the drive it is possible to make these electromagnetic signals emit between 240 and 480MHz, by changing the voltage. These can be picked up by a nearby receiver for about thirty dollars with the GNU Radio software.

The researchers will not elaborate on the exact distance that can be bridged in this way, but the accompanying video shows that this cannot be more than a few meters. Ars Technica is talking about a distance of just under three meters with a small USB drive. With a larger specimen, a distance of almost eight meters would also be feasible. The transfer rate that can be achieved in this way is 80 bytes per second, which allows a 4096-bit encryption key to be transferred in about ten seconds. The technique works with any drive that supports USB 2.0, the researchers said.

The question remains whether the technology can actually be used in realistic scenarios, because a possible attacker must first provide the computer with the USBee software and an external USB drive must also be present. Nevertheless, it is an interesting technique to use standard hardware. Researchers from the same university also recently presented the DiskFiltration technique, which allows information to be transferred by producing sound with the actuator of a hard disk.

Demonstration of the USBee software