Auracast, the new Bluetooth LE Broadcast Audio feature has gained some publicity in the last few months. The Bluetooth SIG has been working on the specification of this feature set in the past few years and vendors are only now starting to implement it. Auracast enables broadcasting audio to multiple devices. These broadcasts can also be encrypted. Unfortunately, the security properties of the protocol are vague and insufficient. It has already been shown that these broadcasts can be hijacked by anyone when unencrypted.

We explain the state of (in)security of the protocol and add to it by showing that even when encrypted, broadcasts can often be cracked easily. We also show that once equipped with the passcode, attackers can eavesdrop and hijack even encrypted broadcasts. Alongside the talk, we will release our toolkit to brute-force authentication codes, decrypt dumped Auracast streams, and hijack encrypted broadcasts.