Hacking Voice Assistants with Ultrasonic Waves

I previously wrote about hacking voice assistants with lasers. Turns you can do much the same thing with ultrasonic waves: Voice assistants -- the demo targeted Siri, Google Assistant, and Bixby -- are designed to respond when they detect the owner's voice after noticing a trigger phrase such as 'Ok, Google'. Ultimately, commands are just sound waves, which other researchers...