After reading excerpts of Sue Kim's new book Without You There Is No Us, I'm confused how anyone in North Korea could pull off the Sony hack. She's said that the internet wasn't accessible to anyone in the country until 2011. You need years worth of crypto and network-security-protocol experience to even pull this off (sidebar: They also haven't left a single trace of who they are anywhere.)
If it was perpetrated by North Korea, then they had to get an outside black-hat contractor. Today was the first day I saw some outlets presenting the idea that the third party could be the Chinese. However I get skeptical whenever the Chinese are accused of hacking. It's a little known secret that attacks originating in China, are for the most part NOT coming from anyone in their government/country; but are rather being remotely controlled by people in the Western/Eastern-European world. (they have a lot of second-hand PCs that are pre-loaded with malware)
It all just seems so weak to me right now, and isn't this exactly why the NSA justifies direct access to underwater cables? There are very few nations that could pull this off: Russia, China, U.S., Israel, Japan, UK, Germany and India. Those are the only ones that even come to mind that could TECHNICALLY do it, nevermind the motive.
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Off topic: This map claims to be a live map of DDOS attacks, it's cool if you haven't checked it out before:
http://map.ipviking.com/