(Cyberwar.news) North Korea hacked into some 140,000 computers belonging to 160 South Korean companies and government entities, Seoul’s intelligence agency has said, as part of a long-term effort by Pyongyang to prepare for a massive cyberwar against its southern neighbor.

As reported by Reuters, the hack was launched in 2014 but was not discovered until February of this year. Hackers targeted a vulnerability in network management software that is used widely throughout South Korea.

South Korea’s cyber investigative unit told Reuters that it had neutralized the malware before it could be employed in a broad cyberattack.

“There is a high possibility that the North aimed to cause confusion on a national scale by launching a simultaneous attack after securing many targets of cyber terror, or intended to continuously steal industrial and military secrets,” an official at the cyber investigation unit told the newswire service.

Officials said around 42,000 documents were stolen by NorK hackers before the intrusion was detected, with 40,000 of them defense-related. The documents stolen included blueprints for the wings of U.S.-made F-15 fighter jets.

Korean Air Lines and SK holdings, a pair of companies identified by media in South Korea as having been victims of the hack, announced that documents stolen were not classified. A South Korean official added further that none of the defense documents were Top Secret.

According to The Wall Street Journal, the IP address used by the NorK hackers was traced to North Korea’s capital of Pyongyang, and was the same one used in a 2013 attack that targeted South Korean banks and TV stations. North Korea has denied involvement.

In recent years North Korea has been increasing its cyber attacks on South Korea. A South Korean spy agency official said that in the previous month attacks coming from NorK hackers had increased two-fold. Targets include the South’s railway control system, financial system networks and the smartphones of about 300 officials.

Regarding the cyber theft of the F-15 wings, South Korea officials said that designs for the plane’s more sensitive parts, like its engines and electronic systems, were not taken, the WSJ reported. The South Korean air force flies F-15s.

“The leak will likely have a negligible impact on national security,” a South Korean military official said.

More:

• Report: U.S. Should Expect More Intense Cyber Attacks From N. Korea
• Did America Lose Its First Cyberwar When Sony Surrendered To North Korean Hackers?
• North Korea Stepping Up Cyber Attacks Against The South

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