Ever heard of Vawtrak? I’m going to give you two links that will explain in detail just what this nasty, nasty Trojan Horse infection is, and how it works.
Link 1: From AVG’s blog This page gives detailed information on this infestation.
And, if you’d like to read the .pdf: You’re most welcome.
Link 2: provides the .pdf information which should be downloadable if you desire. Otherwise, get it yourself from Link 1.
Stay safe online, folks.