In Sony's lengthy response to Congress, the company provided supposed evidence that Anonymous was responsible for hacking into Sony Online Entertainment's servers. They claim that one of the files on the server was named "Anonymous" with the phrase "We Are Legion."
But Anonymous, via a press release, explains that Sony is full of it:
Anonymous has never been known to have engaged in credit card theft. Public support is not gained by stealing credit card info and personal identities. We are trying to fight criminal activities by corporations and governments, not steal credit cards.
I'm not sure if Anonymous is the best practitioner of "gaining public support", but who can we believe at this point? This could be a flat-out fabrication by Sony, or this could just be more Anonymous shenanigans.
Actually, I believe that this mysterious "Anonymous" file is a red herring planted by third-party hackers as a convenient decoy. I don't even think Anonymous would be dumb enough to leave an electronic paper trail as obvious as that.
[Source]