I've got question to anyone that does firmware programming.
I suspect that it is possible to emulate USB device in software. If that's true, how hard would it be to create a virtual usb hub, that the system will treat just like a real usb hardware, and would it require any special privileges on the computer (i.e kernel space module, root).
If it's easy, then I'm worried that it may be possible use this to hide malware this way.
Interesting idea. It would almost certainly require access to the kernel, but you could create a fake USB device (or any other kind of device!) easily. But the fake driver would have to reside on disk where your anti-malware can see it.
The advantage of hiding things in USB keys' firmware is that it can't be seen by normal scanners.
If it's easy, then I'm worried that it may be possible use this to hide malware this way.