Who pulled the plug on North Korea's Internet?

Washington (AFP) - North Korea's Internet was on the fritz for a second day Tuesday. But the US is staying silent on whether it launched a cyber attack as payback for the hacking of Sony Pictures.

Did the US launch a cyber attack on North Korea?... And in the murky world of cyber security, experts say there are several plausible scenarios for why North Korea suddenly went dark, stressing it's impossible to know exactly what happened .... http://news.yahoo.com