Sony hack: growing doubts that North Korea was responsible

Experts contradict FBI assertion that North Korea hacked into Sony, as one analyst points finger at disgruntled employee

The FBI's assertion that Sony's computers were hacked by North Korea in revenge for The Interview depicting the assassination of Kim Jong-Un has been challenged by security experts.

Other potential culprits included a disgruntled former employee or outside hackers, possibly from Russia.

The suggestion that the attack was an "inside job" was made by Kurt Stammberger, a senior vice president with Norse, a Californian cyber security firm.