This is a fascinating story in WIRED: North Korea Hacked Him. So He Took Down Its Internet
It may seem far fetched, but if you read it you can see there were plenty of opportunities for him to exploit weaknesses in North Korea’s networks. He’s also modest about what he was able to accomplish.
Among other things, it reminded me that the Internet is full of fragile technology that can be brought down. Even if that technology is owned by government agencies.
Smart People I Know 
Yeah, I read this a few days ago. I was amazed, but I am not much of a hacker.
It really is amazing. It also shows the brittleness of the Internet everywhere