Reports are stating that Sony has linked North Korea to the cyberattack against their company:

A Sony Pictures internal investigation has identified North Korea as the source of a devastating computer attack, and the studio is deliberating whether to announce the findings publicly, according to a person familiar with the discussions.
The company’s investigation has linked the hackers that stole a major holiday film release and unleashed a destructive computer worm to a North Korean group known as DarkSeoul, which was responsible for similar attacks on South Korean banks and television studios last year, a second person familiar with the investigation said. [Stars & Stripes]
I don’t think there is much Sony can do about this other than they need to improve their network security from these attacks. If North Korea was able to do this imagine what the Russians or Chinese could do with their advanced hacking operations? Companies need to make network security a top priority.
For people in North Korea that were unlucky enough to be named “Jong-un” when they were born, they now have to change their name:

North Korea has ordered its people not to use the name “Kim Jong-un” in a bid to protect the supreme authority of the current leader, according to Pyongyang’s official document confirmed Wednesday.
In January 2011, then leader Kim Jong-il issued a decree urging people with the same name to change it “voluntarily.” As North Korea is regarded as a totalitarian state, it is unclear whether the decree was actually voluntary.
The North has also prohibited parents from registering their newborn babies with the current leader’s name, according to the document titled “a task to achieve.” The use of the given name “Jong-un” is also banned.
While unthinkable in most other countries, the rules are not new in the state long ruled by the Kim family. [Yonhap]
North Korea has reportedly began their routine winter training cycle with Kim Jong-un giving tips to an artillery unit:

The North Korean military has kicked off a winter exercise at the instruction of leader Kim Jong-un, Pyongyang’s state media reported Tuesday.
All troops of the Korean People’s Army (KPA) started “the new year combat and political drill,” said the Korean Central News Agency (KCNA).
The North’s military routinely holds such training from December through March.
The North’s leader chose an artillery unit for his first “field guidance” during the defense exercise season.
He inspected “the Artillery Company under KPA Unit 963,” teaching ways to make the company “one of the crack shots by conducting the drill suited to the nature of its combat duty,” according to the KCNA. [Yonhap]
You can read more at the link.
Like with most things from North Korea who knows if this is true or not:

North Korean leader Kim Jong-un has ordered the country’s senior officials not to smoke foreign cigarettes, saying it is a matter of patriotism, a source said Tuesday.
Kim, who is apparently a habitual smoker himself, said he sees no need for foreign cigarettes in his country as domestic ones have good quality as well, according to the source involved in trade with North Korea.
Kim said smoking foreign cigarettes means a lack of patriotism, added the source based in China. [Yonhap]
You can read more at the link.
It seems that North Korea would be the likely suspect for such an attack, but a skilled criminal group could have used the dispute between North Korea and Sony as good cover for their own hacking attack:

Could an upcoming Seth Rogen–James Franco satire about North Korea have triggered last week’s devastating computer attack on Sony Pictures Entertainment?
On Sunday, Sony internet technicians were still wrestling with the fallout from a paralyzing hacker attack the previous Monday that left the computer, email and phone systems at the TV and movie studio inoperable. A group calling itself Guardians of Peace claimed responsibility for the attack and threatened to release sensitive corporate data.
But Sony has not identified the source of the takedown, according to an individual with knowledge of the situation. Among the theories investigators are checking is that North Korea, or someone operating on its behalf, launched the cyber attack in retribution for “The Interview,” another knowledgeable individual told TheWrap. The upcoming Sony comedy film features Rogen and Franco as journalists who land an interview with reclusive North Korean leader Kim Jong-Un, and are then asked by the CIA to assassinate him. [Yahoo]
You can read more at the link, but if North Korea did do this they have only further given Sony free publicity for this movie that will only increase the number of viewers of it.

North Korean leader Kim Jong Un poses for pictures with female pilots as he provides field guidance to the flight drill of female pilots of pursuit planes of the KPA Air and Anti-Air Force in this undated photo released by North Korea’s Korean Central News Agency (KCNA) in Pyongyang November 28, 2014. REUTERS/KCNA