I’m cynical about these stories in the main stream media, they currently lack a credible source.
And with comments like:

The administration’s sudden urgency came after a new threat was delivered this week to desktop computers at Sony’s offices

So the machines are still compromised? It doesn’t look like they have learnt a security lesson from this incident…

Seems pretty unlikely.

http://marcrogers.org/2014/12/18/why-the-sony-hack-is-unlikely-to-be-the-work-of-north-korea/