A team led by Ang Cui (previously) -- the guy who showed how he could take over your LAN by sending a print-job to your printer -- have presented research at Defcon, showing that malware on your computer can poison your monitor's firmware, creating nearly undetectable malware implants that can trick users by displaying fake information, and spy on the information being sent to the screen.
It's a scarier, networked, pluripotent version of Van Eck phreaking that uses an incredibly sly backchannel to communicate with the in-device malware: attackers can blink a single pixel in a website to activate and send instructions to the screen's malware.
What's more, there's no existing countermeasure for it, and most monitors appear to be vulnerable.
In practice, Cui said this could be used to both spy on you, but also show you stuff that’s actually not there. A scenario where that could dangerous is if hackers mess with the monitor displaying controls for a power plant, perhaps faking an emergency.
“Can I get you to shut down the power plant?” Cui asked rhetorically, with a sly smile. “I can do that.”
The researchers warn that this is an issue that could potentially affect one billion monitors, given that the most common brands all have processors that are vulnerable.
A Monitor Darkly: Reversing and Exploiting Ubiquitous On-Screen-Display Controllers in Modern Monitors [Ang Cui, Jatin Kataria and Francois Charbonneau/Defcon]
Hackers Could Break Into Your Monitor To Spy on You and Manipulate Your Pixels [Lorenzo Franceschi-Bicchierai/Motherboard]
(Image: Madonna in Oslo - Game Over, Ivar Abrahamsen, CC-BY-SA)