  In recent years researchers have demonstrated how attackers could use USB
connectors implanted with RF transmitters to exfiltrate data from secure, and
even air-gapped, computers (e.g., COTTONMOUTH in the leaked NSA ANT catalog).
Such methods require a hardware modification of the USB plug or device, in
which a dedicated RF transmitter is embedded. In this paper we present USBee, a
software that can utilize an unmodified USB device connected to a computer as a
RF transmitter. We demonstrate how a software can intentionally generate
controlled electromagnetic emissions from the data bus of a USB connector. We
also show that the emitted RF signals can be controlled and modulated with
arbitrary binary data. We implement a prototype of USBee, and discuss its
design and implementation details including signal generation and modulation.
We evaluate the transmitter by building a receiver and demodulator using GNU
Radio. Our evaluation shows that USBee can be used for transmitting binary data
to a nearby receiver at a bandwidth of 20 to 80 BPS (bytes per second).
