North Korean hackers are believed to have stolen more than US$90 million from banks overseas last year, computer security firm Symantec said Wednesday.

Symantec analyzed cyber crimes around the world last year and fingered North Korean hackers in attacks on 104 banks in 30 countries, including a heist on the central bank of Bangladesh that netted $81 million.

Symantec analyzed the malicious code used in the Bangladesh heist and concluded that it was the same as the one used by a group called Lazarus, which is thought to be linked with the North Korean regime. The group was behind the 2014 attack on Sony Pictures' Hollywood studio, and the FBI blamed it on North Korea as it occurred before the release of the caper "The Interview," about the attempted assassination of North Korean leader Kim Jong-un.

The hackers obtained a security code for the central bank of Bangladesh and stole the money by asking the New York Federal Reserve Bank to transfer funds in the central bank's account to the Philippines and Sri Lanka.

Some of the money was recovered when authorities became suspicious, but most of it was lost.

Yoon Kwang-taek at Symantec Korea said, "Lazarus was discovered to have been behind cyber attacks targeting banks in Vietnam, Ecuador, the Philippines and Poland since 2015," stealing altogether $94 million.

