The OS can't look at the device until it's plugged in (obviously); the device plugs into the USB bus, which then gets compromised before the OS even knows anything is there.
To extend my (now hilariously) tortured analogy, granny is stuck in bed, she can't check if it's a wolf until the butler knows there's someone at the door. As soon as he sees the wolf, he is compromised. Maybe a vampire would have been a better metaphor?
[EDIT] actually I should dump the analogies altogether: this is a hardware vulnerability, not software. It hits the computer, the operating system is helpless. That’s why the problem, for existing computers, is not apparently fixable.
To extend my (now hilariously) tortured analogy, granny is stuck in bed, she can't check if it's a wolf until the butler knows there's someone at the door. As soon as he sees the wolf, he is compromised. Maybe a vampire would have been a better metaphor?
[EDIT] actually I should dump the analogies altogether: this is a hardware vulnerability, not software. It hits the computer, the operating system is helpless. That’s why the problem, for existing computers, is not apparently fixable.