According to Alan Woodward, a UK based cyber security professor, a link could be possible to the ransomware attack known as WannaCry and the Lazarus hacker group. A group that allegedly operates out of China on behalf of the North Korean government.
These claims have been made after one of Google's security experts, Neel Mehta, found a similarity between the code used in WannaCry and code used by the Lazarus Group in cyber attacks on Sony and Bangladesh in the past. Even a Russian cyber security firm, Kaspersky has also confirmed that this is potentially the first sliver in any evidence as to the origin of the global attack that started last Friday. Below is the tweet from Google's Neel Mehta revealing the code supposedly linked to the Lazarus group:
With all this being said, none of these sources declare that this is enough information to make any claim or basis of actual blame. Much more digging and cooperation will be required before a consensus can be reached. Considering the attack has affected China and Russia quite substantially, who could be considered the North Korean government's biggest allies, the allegation that this was initiated by them raises even more oddities in the claim.
Additionally this small piece in the puzzle is somewhat at odds with what Microsoft's President and Chief Legal Officer said only a few days ago, wherein they had implicated government agencies such as the NSA in particular for developing and stockpiling such cyber weaponry.