Date: April 2011
Affected: 77 million
What seemed like an ordinary service outage for Sony's online gaming and movie service became notorious for being one of the biggest online breaches ever. In April of last year, hackers gained access to over 77 million PlayStation Network accounts, with 12 million unencrypted credit card numbers as well as user information like full names, passwords, and purchase history. The debacle would prove to be just the first in a series of attacks against the tech giant, with Sony Online Entertainment and Sony Pictures also eventually falling prey.