Experts are questioning whether North Korea was behind the WannaCry cyberattack attack, saying it doesn't fit the pattern of previous hacks blamed on Pyongyang.
Identifying hackers behind sophisticated attacks is a notoriously difficult task. Proving they are acting under the explicit orders of a nation state is even trickier. Some suspect a group known as Lazarus, believed to be a mixture of North Korean hackers operating in cahoots with Chinese "cyber-mercenaries."
But some experts see the latest attack as an anomaly.
Michael Madden, a visiting scholar at the Johns Hopkins School of Advanced International Studies and founder of North Korea Leadership Watch, says if North Korea were behind it, it would be an entirely new type of cyberattack by Pyongyang. Others say the evidence is circumstantial at best.