[I'm surprised that my searches didn't find this questions before, but then I may just not be asking it "the right way."]
A project I am on is starting to look a threat trees for a connected piece of hardware that is under development. As a start, we decided to look at a simple entry point, the USB port. That took up most of the meeting, and is still incomplete.
I am pretty certain we are not the first or last team ever to consider the attack surface presented by a USB port. That begs my main questions
Is there a library of common attack trees exist?