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Military network found to have been stymied during November network blackout

South Korea’s military network was found to have been paralyzed during a massive network disruption last month, sparking criticism over the government’s attempt to downplay the incident that plunged the nation into a chaos.

According to a document submitted by the Ministry of National Defense on Monday to an opposition lawmaker, a total of 28 internal military networks came to a halt after a fire at a building of the country’s No. 2 mobile carrier caused a massive blackout on Nov. 25. 

Among the damaged network systems was one that connects a secret wartime bunker with the combined command of South Korea and the US. Both facilities were said to have been linked by the damaged KT network that bought down landline, mobile and internet services in parts of western Seoul. 

While the Defense Ministry acknowledged that the military network was damaged by the massive blackout caused by a fire at the KT building, the incident did not take a significant toll on major units’ combat capabilities.

“Major combat units have their own communication system within the military, so they were not influenced by the fire incident at all,” Defense Ministry’s spokesperson Choi Hyun-soo said during a press briefing.


“After the incident happened, the military assessed the damage promptly, placed priorities for a recovery mission and carried it out accordingly … there were no problem in maintaining readiness posture.”

But criticism persists that the Defense Ministry was seeking to downplay the damage it suffered from the network blackout, with concern rising over whether the military has an adequate back-up communication system in the event of contingency.

Days after the network blackout swept across Seoul, the Defense Ministry said its internal military network was not damaged by the fire at KT. While some incoming calls to the ministry did not work temporarily, it was recovered promptly, the ministry said.

Among the most worrisome was the malfunctioning of the KJCCS network system operated by the Joint Chiefs of Staff, analysts said. Through the network, the JCS shared classified intelligence with different service branches and US forces in Korea.

“From the military’s point of view, the KJCSS program is like air. Therefore, the military might not have been prepared for the worst-case scenario in which the KJCSS doesn’t work,” Shin Jong-woo, a senior analyst at the Korea Defense and Security Forum, told Chosun Ilbo.

Mobile and internet networks in the western Seoul went down after the fire broke out in the basement of the KT building on Nov. 25. Cash machines and in-store payment systems provided by KT were also paralyzed.