The only industry successful at battling the pirates is the game console business.
http://www.eurogamer.net/articles/20...halo-4-pirates
Hollywood, Recording Companies and Ebook publishers have been largely unsuccessful. Unless a company monitors your content and continually updates the firmware or application software, it's does not stand a chance of thwarting pirates, or fair use advocates. ADE has not been updated in years on my machine. If the publishers want more protection, then they need to pay Adobe to robustify their software.
As far as the vector through which an infection would enter your machine, most likely the "enemy" would try to exploit a stack overflow in Calibre, either in a plugin or its reader/viewer.