SoK: Security in the Inaudible World

Ultrasound and near-ultrasound acoustic frequencies offer non-intrusive and low-overhead mediums for data transmission protocols. These protocols and the technologies built upon them are becoming more prevalent, yet their security remains largely unexplored. We present the first systematization of ultrasound and near-ultrasound enabled applications, developing a unified threat model to address their security. Our analysis reveals misguided assumptions, missing protections, and the need for standardization. Through our taxonomy, we highlight key insights, future research directions, and propose a framework for securing these protocols.