Two long-time members of Anonymous spoke to the Financial Times and stated that it’s possible that other group members are responsible for hacking PSN. A member of Anonymous told FT that he had seen technical details of the vulnerability on Sony’s network that enabled the break-in discussed on an Anonymous chatroom shortly before the intrusion.
“If you say you are Anonymous, and do something as Anonymous, then Anonymous did it,” said the hacker, who uses the online nickname Kayla. “Just because the rest of Anonymous might not agree with it, doesn’t mean Anonymous didn’t do it.”
Source – FT