Better known as P4x or _hyp3ri0n, this cybersecurity expert was recruited by the US government after his exploit. Disillusioned, he has decided to reveal his identity and continue the fight on his own
(...) the internet went down across the country. A wave of cyberattacks left all systems on hold for more than seven days. First, the main national websites failed, from the official news site to the booking page of the national airline. Then, the Asian state’s connections with the rest of the world were interrupted. Emails could not be sent or received; there was no connection to cloud services. The blockade was complete.
What normal people hear: "He took down the routers with some crazy complicated algorithms. He's Neo in the matrix."
What IT professionals hear: "He hired a bunch of people to keep sending spam letters to their tiny mailboxes until they were so stuffed that they couldn't receive any legitimate mail."
Unless things have changed, North Korea doesn't have a whole lot by way of Internet. I think they used to have two Class C netblocks, 256 IP addresses each.