The reason for the attack is political
"Yet the technology news site Re/code reported that Sony was investigating to determine whether hackers working on behalf of North Korea were responsible for the attack as retribution for the company's backing of the film "The Interview."
The movie, which is due to be released in the United States and Canada on Dec. 25, is a comedy about two journalists recruited by the CIA to assassinate North Korean leader Kim Jong Un. The Pyongyang government denounced the film as "undisguised sponsoring of terrorism, as well as an act of war" in a letter to U.N. Secretary-General Ban Ki-moon in June.
The technical section of the FBI report said some of the software used by the hackers had been compiled in Korean, but it did not discuss any possible connection to North Korea.