In the Sony cyberattack, hackers have used tactics that are unlikely to be associated with state-sponsored attacks, according to experts. Reuters

North Korea is not likely to be behind a massive breach of the computer systems at Sony Pictures Entertainment, which led to the leak of unreleased movies and confidential internal documents, according to experts.

The cyberattack, which forced Sony to shut down its systems late last month, has been linked to North Korea because the code used in the hack was the same used in an attack aimed at South Korea in March 2013, which disabled ATMs and crippled several websites. Some reports had also suggested that the hackers that breached Sony’s networks were backed by the North Korean government in retribution for the studio's support for “The Interview,” a comedy about a CIA attempt to assassinate North Korean leader Kim Jong Un.

However, Lucas Zaichkowsky, an enterprise defense architect with Resolution1 Security, said that the tactics used by the hackers against Sony were unlikely to be associated with state-sponsored attacks, PC World reported. Zaichkowsky also told PC World that the decision to publicly release gigabytes of data was more likely to be a move by hacktivists. Guardians of Peace (GOP), the hacking group that has claimed responsibility for the attack, has also said that it was not working on behalf of any government.

“Sony and Sony Pictures have made terrible racial discrimination and human rights violation, indiscriminate tyranny and restructuring in recent years,” GOP wrote in an email, reportedly obtained by PC World. “It has brought damage to a lot of people, some of whom are among us.”

Meanwhile, North Korea too has denied allegations that it was behind the Sony cyberattack.

“Linking [North Korea] to the Sony hacking is another fabrication targeting the country,” a Pyongyang diplomat in New York told Voice of America. “My country publicly declared that it would follow international norms banning hacking and piracy.”

North Korea’s denial came after a North Korean spokesperson to the United Nations refused to rule out Pyongyang’s involvement in the latest hack. The government representative had responded with the remark, “Just wait and see” to questions about who was responsible for the attack, the Guardian reported.