I suppose the fundamental problem is treating the thing on the other end of the wire as a "peripheral" (i.e. inside the computer's logical boundary) rather than as another computer on the end of a network (which might be expected to be hostile).
Firewire and Thunderbolt are much worse: the peripheral has potential DMA access to the whole of system memory. http://support.microsoft.com/kb/2516445
I suppose the fundamental problem is treating the thing on the other end of the wire as a "peripheral" (i.e. inside the computer's logical boundary) rather than as another computer on the end of a network (which might be expected to be hostile).
Firewire and Thunderbolt are much worse: the peripheral has potential DMA access to the whole of system memory. http://support.microsoft.com/kb/2516445