https://www.techradar.com/news/someone-is-tricking-voice-assistants-with-white-noise-and-secret-commands

Ever get the feeling that your voice assistant of choice isn't doing what you actually want it to do? Well, it might not be your dodgy accent to blame as a bunch of researchers have found ways to manipulate the likes of Siri and Alexa, using white noise and a series of commands not audible to us puny humans. 

According to the New York Times, researchers at the University of California, Berkeley, have revealed how they managed to embed commands directly into music or spoken word that could potentially get a voice assistant to add something to a shopping list or control parts of a phone.