Quote:Researchers have discovered a new way to hack Alexa and Siri smart speakers merely by using a laser light beam. No physical access of the victims’ device, or owner interaction, is needed to launch the hack, which allows attackers to send voice assistants inaudible commands such as unlocking doors.
 
The attack, dubbed “light commands,” leverages the design of smart assistants’ microphones. These are called microelectro-mechanical systems (MEMS) microphones, which work by converting sound (voice commands) into electrical signals – but in addition to sound, researchers found that MEMS microphones also react to light being aimed directly at them.
 
Researchers said that they were able to launch inaudible commands by shining lasers – from as far as 110 meters, or 360 feet – at the microphones on various popular voice assistants, including Amazon Alexa, Apple Siri, Facebook Portal, and Google Assistant.

“[B]y modulating an electrical signal in the intensity of a light beam, attackers can trick microphones into producing electrical signals as if they are receiving genuine audio,” said researchers with the University of Michigan and the University of Electro-Communications (Tokyo) in a Monday research paper.