The malicious code acts like a keyboard or mouse, there is no need for something to open and install.
Alright, this article explains everything really well. If you don't know what you're talking about (which is pretty much everyone here including me) then read this and itll explain it: http://www.theregister.co.uk/2014/07/31/black_hat_hackers_drive_truck_through_hole_in_usb_security/
I know exactly what it's doing lol.
So couldn't they just release an OS patch where when you plug in a usb device it says, is this a keyboard?
Its inherent in the USB platform itself, the firmware. You can't fix that without replacing every single USB and USB dock in the world.
You could have computers not just accept USB the way they do. USB device says, "I am X type of USB device." Computer says, "you are a storage device until I decide otherwise."
Then how would you go about setting up a fresh computer, using a keyboard or mouse interface? There would be no OS to install drivers or decide otherwise.
Plus, what if there is no OS to do this check? Again, its an inherent USB problem.