In tests, the team managed to steer an app-controlled toy car by playing carefully crafted music through an Android phone's speaker. They also got a phone to spell out the word "walnut" in a graph through another piece of music, and made a Fitbit tracker record imaginary steps using a basic speaker. None of these specific attacks are particularly frightening, but the team notes that this could theoretically be used to hijack drones or other vehicles that depend on motion sensing to get around.

The good news: this is relatively easy to defend against. There are two "low-cost" software solutions to thwart the resonant frequency exploit, and the researchers have already reached out to manufacturers (including Fitbit and Samsung) to make sure they're aware of the issue. This particular vulnerability might not last long. However, it's still an eye-opener -- it shows that sensor security can be just as important as the operating system or your apps.