Hackers in North Korea got access to Oplan 5027

When South Korea’s defense intranet was hacked for the first time ever last September, the military was swift to point the finger at the North, accusing Pyongyang of contaminating 3,200 computers with malware, including that of National Defense Minister Han Min-koo.

Briefing lawmakers in the parliamentary National Defense Committee in December, Han admitted that confidential data was leaked but said it wouldn’t have any “serious implications.”

Han’s definition of serious was challenged Monday night when the state-run Korean Broadcasting System (KBS) reported that North Korean hackers gained access to Operations Plan 5027 (Oplan 5027) - the main military plan by the South Korea-U.S. allied forces to react to a possible North Korean invasion.

Oplan 5027 is the most recent such plan drawn up by the United States and South Korea.

KBS reported that a joint investigation by military prosecutors, the Defense Security Command and the National Intelligence Service concluded last month that Oplan 5027 had been compromised.

Investigations were ongoing, KBS said.

Multiple sources in the Ministry of National Defense confirmed the report Tuesday when asked by a reporter from the JoongAng Ilbo, an affiliate of the Korea JoongAng Daily.

“A total of 5,000 computers or more turned out to have fallen victim to the malware,” said a military official who has knowledge of the investigation but asked for anonymity because he wasn’t authorized to share the results with media.

“We’ve detected signs of infiltration in the computer networks of the ROK-US Combined Forces Command and the Joint Chiefs of Staff,” the source continued.

Another military source said it was “meaningless” to predict precisely how far North Korea was able to break through the system because among the first places hacked was the Defense Integrated Data Center, the military intranet hub where all South Korean defense information is integrated and stored.

“It’s difficult to gauge how much confidential military information the North actually gained from the hacking,” a government official agreed. “But North Korea is capable of taking several ordinary documents and adding it all up to draw a big picture of our military secrets.”

BY LEE SUNG-EUN, LEE CHUL-JAE [lee.sungeun@joongang.co.kr]