French researchers have demonstrated how it might be possible to take control of your smartphone from a distance, using radio waves and voice control. The hack is clever, but of little real concern, given its complexity and limited utility.
The hack works on phones with headphones plugged in and which are set to allow voice control from the lock screen. A radio wave is transmitted which induces an electrical current in the headphone wire that mimics a voice command. Given that the command is being generated electronically it's safe to assume that a well planned attack would ensure that the signal was perfectly understood by your phone.
So what are the risks?
First off, there are only limited actions that voice control will allow from the lock screen. Most of those involve some form of voice feedback, not to mention the audio tone that all smartphones play when their voice assistant is enabled. A user wearing headphones - either for voice calling or listening to music, would be immediately alerted that something strange was happening. For those people who leave their phones on a desk or a backpack with headphones connected, there's more of a risk.
However given that all three operating systems require you to train their voice assistants to your voice, it's increasingly unlikely that this hack would get very far.
I certainly won't be disabling voice recognition on my phones because of this news, however if you are the sort of person who is cautious about these things and you regularly leave your phone with its headphones plugged in, you may want to change that behavior.