The worst hacks of all time

Experian unknowingly sold the personal data of millions of Americans to a fraudster, who then sold that to identity thieves around the globe, putting the information in a database that criminals accessed 3.1 million times.

Hieu Minh Ngo, a scam artist in Vietnam. posed as a private investigator in Singapore to get exclusive access to data via Court Ventures, an Experian subsidiary. The data included names, addresses, Social Security numbers, birthdays, work history, driver's license numbers, email addresses and banking information.

Experian has stayed mum on the attack, so it's impossible to know exactly how many people were impacted. But security experts believe the fallout could ultimately be one of the largest attacks ever -- if not the largest.