LULZSEC

The reason for the attack? Apparently because Fox.com had described a rapper called Common as "vile" on-air.

http://www.theguardian.com/technology/2013/may/16/lulzsec-hacking-fbi-jail


Lulzsec is a break off sector of anonymous which enjoy exercising there power over the internet just for the laugh of it. The people behind it contracted away from the moral views of "lulz" another sector which was the first to be established. The sectors originated from a chatroom culture of  laughs and rebellion against what most of them believed the wrongs in the world.  

This is a huge attack from lulzsec against foxnews over a comment which was so small - Lulzsec felt that was bad so as a community of hacktervist they leaked files and brought havoc to the whole world just for a laugh.