No. There is independent analysis pointing at a group called 'Lazarus' which is believed to be linked to North Korea.

So, it's either a North Korean group, or a group shielding their identities pretending to be North Korean.

Given the lack of publicly available evidence linking the group to NK, and the sophistication of the majority of the things attributed to them, I personally have a very difficult time believing that NK would be capable of these things.. as this would mean extremely talented computer skills, which to develop would require unfettered access to the entire internet for extremely long periods of time, knowledge of several languages, and a host of skill sets that are not usually you'd associate with living in an oppressive regime that can barely keep the power on.

I'm going to go with Occam's razor on this one because it's far more likely that it's easier to pretend to be from NK than for NK to do what they are being accused of.