2011 PlayStation Network outage

The 2011 PlayStation Network outage (sometimes referred to as the 2011 PSN Hack) was the result of an "external intrusion" on Sony's PlayStation Network and Qriocity services, in which personal details from approximately 77 million accounts were compromised and prevented users of PlayStation 3 and PlayStation Portable consoles from accessing the service. The attack occurred between April 17 and April 19, 2011, forcing Sony to deactivate the PlayStation Network servers on April 20.

Source: Wikipedia — 2011 PlayStation Network outage (CC BY-SA 4.0)