Wednesday's report exposes serious risks in what banks, mortgage companies, and other financial services call "knowledge-based authentication." Representatives from these services frequently rely on a list of about 100 questions such as "What was your previous address?" or "Which company services your mortgage?" when trying to determine if the person on the phone or filling out an application is the individual he claims to be. Ready access to the data stored by the data aggregators can make the difference between a fraudulent application being approved or rejected. Krebs goes on to recount a story told by Gartner fraud analyst Avivah Litan about a fellow analyst who witnessed an identity thief in action.