seiters

Thanks for the comment. This defense works: but you have to remember to lock your phone when you put it down.

Not necessarily. Both Android and iOS allow voice assistants to interact with phones for certain activities even without unlocking the phones. Typical scenario: someone puts a phone on the table and does something else (typing on a computer), not paying attention to the screen.

SurfingAttack exploits ultrasonic guided wave propagating through solid-material tables to attack voice control systems. Interesting!