Researchers just found yet another reason to be paranoid: Even if hackers or the NSA are locked out of your cellphone's microphone, camera and data, they might still be able to snoop on you through the tiny chip that tracks the device's orientation. Gyroscopes in modern phones, unlike the spinning gyroscopes of old, work by a method that also allows it to detect vibrations in the air at certain frequencies — including some that overlap with the human voice. And worse still, Android apps don't have to alert the user that they're accessing the gyro, meaning practically any game or website could be listening in on you (neither do iPhone apps, but the technique doesn't work as well on iOS).
Fortunately the vulnerability, described by researchers at Stanford and Israeli defense firm Rafael, appears to be largely theoretical, and it has some serious limitations even if someone were to pull it off. The gyro can only detect the lowest frequencies of the human voice — enough perhaps to discern between two voices or clearly spoken words, but not understand conversations. Still, it's possible in principle — and hopefully Google will do something about it soon.