http:// www.investmentwatchblog.com/ultrasonic-attacks-can-trigger-alexa-and-siri-with-hidden-commands-raise-serious-security-risks/

For instance, a millennial could be listening to their favorite song: ‘The Middle’ by Zedd, Maren Morris & Grey. Embedded into the audio file could have several inaudible commands triggering Apple’s Siri or Amazon’s Alexa to complete a task that the user did not instruct — such as, buying merchandise from the music performer on Amazon.

DolphinAttack could inject covert voice commands at 7 state-of-the-art speech recognition systems (e.g., Siri, Alexa) to activate always-on system and achieve various attacks, which include activating Siri to initiate a FaceTime call on iPhone, activating Google Now to switch the phone to the airplane mode, and even manipulating the navigation system in an Audi automobile.