BLUFFS: Bluetooth Forward and Future Secrecy Attacks and Defenses
Daniele Antonioli · 2023
Bluetooth is a pervasive technology for wireless communication. Billions of devices use it in sensitive applications and to exchange private data. The security of Bluetooth depends on the Bluetooth standard and its two security mechanisms: pairing and session establishment. No prior work, including the standard itself, analyzed the future and forward secrecy guarantees of these mechanisms, e.g., if Bluetooth pairing and session establishment defend past and future sessions when the adversary compromises the current. To address this gap, we present six novel attacks, defined as the BLUFFS attacks, breaking Bluetooth sessions' forward and future secrecy. Our attacks enable device impersonation and machine-in-the-middle across sessions by only compromising one session key. The attacks exploit two novel vulnerabilities that we uncover in the Bluetooth standard related to unilateral and repeatable session key derivation. As the attacks affect Bluetooth at the architectural level, they are effective regardless of the victim's hardware and software details (e.g., chip, stack, version, and security mode).