It is Possible to Hack a Phone With Sound Waves

This NY Times article describes research by Dr Wenyuan Xu and colleages at the University of Michigan into how to maliciously control a phone's accelerometer using sound waves.

In their paper, the researchers describe how they added fake steps to a Fitbit fitness monitor and played a "malicious" music file from the speaker of a smartphone to control the phone’s accelerometer. That allowed them to interfere with software that relies on the smartphone, like an app used to pilot a radio-controlled toy car.

The video below explains their research.

The image is taken from their paper.