Security researchers from Ben-Gurion University present USBee, a proof-of-concept of a type of malware that can bypass airgapped computer systems by wirelessly transmitting data via the drive data bus. The technique works on just about any storage device that's compliant with the USB 2.0 specification, no radio frequency transmitting hardware is needed as the method uses the USB device's internal data bus.
Using a nearby receiver device, which costs around $30 to assemble, an attacker could exfiltrate data from an airgapped PC. It's a slow process though, USBee transmits data at a rate of 80 bytes per second.
And while it's a very neat trick, it seems very impractical for real-world situations as you need to be able to compromise the machine and have write access to the USB drive. If both conditions are met, it's probably a lot easier to just write the data to the USB drive. Full details at ARS Technica.
The software works on just about any storage device that's compliant with the USB 2.0 specification. Some USB devices such as certain types of cameras that don't receive a stream of bits from the infected computer, aren't suitable. USBee transmits data at about 80 bytes per second, fast enough to pilfer a 4096-bit decryption key in less than 10 seconds. USBee offers ranges of about nine feet when data is beamed over a small thumb drive to as much as 26 feet when the USB device has a short cable, which acts as an antenna that extends the signal. USBee transmits data through electromagnetic signals, which are read by a GNU-radio-powered receiver and demodulator. As a result, an already-compromised computer can leak sensitive data even when it has no Internet or network connectivity, no speakers, and when both Wi-Fi and Bluetooth have been disabled.