This was done as part of Lior Neumann's master's thesis, supervised by Prof. Eli Biham, head of the Hiroshi Fujiwara Cyber Security Research Center.
Prof. Biham said: "The technology we developed reveals the encryption key shared by the devices and allows us, or a third device, to join the conversation. We can eavesdrop on or sabotage a conversation. As long as we do not actively participate, the user has no way of knowing that there is a third party listening in."
Bluetooth device coupling uses a mathematical concept called elliptic-curve cryptography (ECC). At the moment of coupling, the Bluetooth devices use points on a mathematical structure called an elliptical curve to determine a common secret key on which encryption is based.
The Technion researchers found a point with special properties located outside the curve, which allows them to determine the result of the calculation without being identified as malicious by the device. Using that point, they set the encryption key that will be used by the two coupled components.
The offensive developed by Neumann and Prof. Biham is relevant to both aspects of Bluetooth technology – the hardware (chip) and the operating system (such as Android or iOS) in both devices (a headset and phone for example) – and threatens the newest versions of the international standard.
The Technion researchers contacted the CERT Coordination Center at Carnegie Mellon University and Bluetooth SIG and informed them of the breach they discovered. "We also contacted major international companies including Intel, Google, Apple, Qualcomm, and Broadcom, which hold most of the relevant market, and informed them about the breach and ways to fix it," said Prof. Biham. "Google defined the breach as 'severe' and distributed an update about a month ago; Apple released an update this week. Other manufacturers who heard about the breach contacted us in order to check their products."