Researchers have demonstrated an ability to “hack” smart speakers and phones, including those from Google, Apple and Amazon, by sending silent commands by laser from as far as 100 metres away.
The researchers, from universities in Japan and the US, spent months developing their experiments and dub the technique “light commands”. In a paper, they describe how the commands could be used from just about anywhere with line of sight to the device, even through windows.
The method exploits micro-electro-mechanical microphones, which are used in many gadgets that are designed to listen for speech. The researchers discovered that such microphones also respond to light, so they could use a laser to transmit a phrase such as “Hey Google, unlock the door”, and the device would react as if the phrase was spoken nearby.
Though some media reports have indicated any attacker could do this with a cheap laser pointer, that isn’t strictly true. The researchers did use ordinary laser pointers in the tests, as well as other relatively common devices including a portable audio amplifier and a telephoto lens designed for cameras. All up this gear cost the researchers $US246, or around $357.