LulzSec
termhackingsecurity
The six-person splinter from Anonymous that ran a fifty-day spree in 2011 - Sony, PBS, the CIA's public site, an FBI affiliate, games companies - announcing each breach on Twitter with a cartoon mascot and mocking the victims' security.
Technically most of it was ordinary SQL injection against neglected websites, which was the uncomfortable lesson: the systems were that easy. The ending is the darker lesson. The leader, Sabu, had been arrested early and ran the crew for months as an FBI informant, which is how the arrests arrived all at once. LulzSec is the standard case study in how a movement with no accountability structure gets rolled up through one person.
Also known as: lulz security, sabu, 50 days of lulz