“It’s really a phenomenally awesome hack—they completely owned this company,” Schneier, who is regularly consulted by the federal government on security issues, said. “But, I think this is just a regular hack. All the talk, it’s hyperbole and a joke. They’re [threatening violence] because it’s fun for them—why the hell not? They’re doing it because they actually hit Sony, because they’re acting like they’re 12, they’re doing it for the lulz, no one knows why.”
Unless you know how infiltrators got into Sony’s system there is no way figuring out the who behind the hack. So far details of this has been lacking and as far as potential culprits targeting Sony, North Korea is probably least capable from an education standpoint and logistics. Social engineering, getting people inside Sony to cooperate is usually behind successful infiltrations. Sony’s Playstation network was taken down awhile ago. I suspect whoever did that probably is behind this despite what movie is about to be released soon.