The standard Alexa has about seven microphones in a circle detecting sound from every direction, McCarty says. “The microphones in your Alexa are MEMs microphones – which are extremely sensitive and can detect sound/pressure changes below and above human hearing ranges. Due to the nature of how the membrane in these microphones are designed, they are always detecting sound, regardless if the Mute is on or not.”
In other words: Alexa can pick up conversations you have without trouble.
Even if you attempt to cover or block sound from the Alexa microphone with tape or pillow, McCarty says it will hear despite barriers.
“The best solution is to unplug it to prevent the MEMs microphones from activating,” McCarty says. “Unplugging will be the best choice until Amazon introduces mechanical microphone disconnect switches into Alexa.”
But why would you even want to unplug your Alexa? Simple: to protect your privacy and security at home.
“There have been several examples where hackers and researchers were able to cause security issues with Alexa by targeting its microphones,” McCarty says. “For example, it was shown that those special and extremely sensitive MEMs microphones will react to lasers shining on them. Combine this with specially crafted laser intensity modulation – a hacker outside of your house could aim a laser through a window at your Alexa and issue commands to it, such as to unlock all smart locks, or order thousands of products off Amazon.”
It is even possible to direct subsonic ultrasonic sound (which you would not hear) like the laser beam to issue silent commands to your Alexa, McCarty says.
“It has also been shown that these MEMs microphones are capable of detecting unique environmental sounds, so if a hacker were to gain unauthorized remote access to your Alexa – they could perhaps detect your physical location with enough data (i.e., airplane flight traffic, weather conditions etc.),” McCarty says. “Multiple Alexa’s in every room could be leveraged by a remote hacker to determine the location of occupants of each room, if they are sleeping based on breathing or other clues as to what’s going on near the Alexa.”
The next best thing to not owning an Alexa is to keep it turned off when you are not using it.