A team of researchers from Ben-Gurion University in Israel has discovered a way to extract sensitive information from air-gapped computers this time using radio frequency transmissions from USB connectors. The attack is a significant improvement over the NSA-made USB exfiltrator called CottonMouth that was mentioned in a document leaked by former NSA employee Edward Snowden. The researchers stress the attack method of USBee is solely based on software, though it has to met certain conditions to execute. USBee transmits data at about 80 bytes per second, which is fast enough to steal a 4096-bit decryption key in less 10 seconds.
Source: https://thehackernews.com/2016/09/usbee-airgap-computer.html