Google's Nest thermostat, poster-child for its Internet of Things ambitions and data collector of your home habits, gives root access to anyone with a USB drive and a quarter-minute to spare.
That's the conclusion that Yier Jin, Grant Hernandez and Daniel Buentello have come to, and told the world in their presentation to BlackHat (abstract here).
While their attack – can it be called an attack when it's so trivial? – needs physical access to the devices for “ten to 15 seconds”, it's very straightforward: press and hold the power button, insert a USB drive, and Nest enters a developer mode.
In the usual you-can't-be-serious cavalier attitude of home automation vendors, Jin's demonstration attack creates a rooted device and bypasses firmware signing.
This, they write, “allows us to backdoor the Nest software in any way we choose … Loading a custom kernel into the system also shows how we have obtained total control of the device”.
And since Nest uses Internet connections to talk to The Chocolate Factory, the same connection can be reprogrammed to report when the owner is home and when they're away, and data like Wifi credentials are available to the attackers.
There's also a real potential for a dodgy operator to buy bulk Nests, interfere with them, and resell them to unsuspecting punters.
It seems to The Register a good idea for people to block Nest at their firewall. ®