Although North Korea continues to deny involvement with the Sony hack, the FBI has officially placed blame on the country after an investigation. The FBI did not release significant details as to how they came to this conclusion (they need to keep some “trade secrets” on how and what information they are obtaining) but Krebsonsecurity.com has a great rundown of a few smoking guns that point to North Korean involvement. That same article notes that independent security company CrowdStrike, which focuses on determining who the actors are behind high profile cyber attacks, said that it came to the same conclusion as the FBI before the FBI even made its announcement.
After the FBI pointed a finger at North Korea, President Obama said that the United States would levy an “appropriate response.” It was unclear what that would be exactly.
It is in no way certain that the United States caused the North Korean internet to go down. North Korean internet is only connected to the rest of the world via four connections that filter through China. It is entirely possible that their internet collapsed due to a DDoS attack, however it is unclear at this time.
Meanwhile, Sony has proceeded to allow their movie “The Interview” to be screened on Christmas day in a small run of theaters that have agreed to show the movie. It seems that the larger theater chains such as AMC and Regal are still not going to run the film yet, but the move by Sony is a good one in terms of not caving to the demands of the unknown hackers.