It would not be surprising if spooks rely mainly on plugging into HDMI to suborn machines now. Of course this is no help with that unless spooks have substituted a doctored monitor. Or cable. The doctored presentation-room projector would be a plausible place for that.
I wonder which of the things that happen when an HDMI cable is plugged in are negotiated in hardware or laptop firmware, before the host system driver gets to talk to it. It's short odds a binary blob for that chip is loaded at startup. So, turning off services that respond at the OS level likely would not suffice. And, does code in that binary blob have full DMA access to the main memory bus, and PCI devices?
Anyway this gadget should protect against the projector.
I wonder which of the things that happen when an HDMI cable is plugged in are negotiated in hardware or laptop firmware, before the host system driver gets to talk to it. It's short odds a binary blob for that chip is loaded at startup. So, turning off services that respond at the OS level likely would not suffice. And, does code in that binary blob have full DMA access to the main memory bus, and PCI devices?
Anyway this gadget should protect against the projector.