Just because some vague articles and politicos point the finger at North Korea doesn't mean that it's true. I'm not making any assertions about the truth at this point, but we should be careful before jumping to (potentially violent) conclusions based on hearsay.
"But in their initial public statement, whoever hacked Sony made no mention of North Korea or the film. And in an email sent to Sony by the hackers, found in documents they leaked, there is also no mention of North Korea or the film. The email was sent to Sony executives on Nov. 21, a few days before the hack went public. Addressed to Sony Pictures CEO Michael Lynton, Chairwoman Amy Pascal and other executives, it appears to be an attempt at extortion, not an expression of political outrage or a threat of war."