Korea Hydro and Nuclear Power Co. Ltd., which runs South Korea’s 23 nuclear power reactors, said on Monday its computer systems had been hacked, raising alarm in a country that is still technically at war with North Korea.
Park ordered inspections of safeguards at national infrastructure facilities, including nuclear power plants, against what she called “cyber-terrorism.”
A government official said authorities had raised the cyber-crisis alert by one level for all the state-run companies from “attention” to “caution.”
The nuclear operator, part of state-run utility Korea Electric Power Corp, said only non-critical data had been stolen and operations of the nuclear plants were not at risk. South Korea’s law enforcement authorities are investigating the leaks.
“Nuclear power plants are first-class security installations that directly impact the safety of the people,” Park said at a cabinet meeting, according to her office.
“A grave situation that is unacceptable has developed when there should have been not a trace of lapse as a matter of national security,” she said.
Within hours of Park’s comments, an online user who claimed to have hacked the nuclear operator posted a new threat and a fresh batch of data on the same Twitter account that was used for previous threats and leaks.
Earlier, the investigation team official said Seoul had not ruled out the possibility that North Korea was involved in the cyber-attack, although Park did not make any mention of it.
The official added that South Korea had requested Washington’s help investigating the matter.
In recent years, South Korea has accused the North of carrying out several cyber-attacks on its banks and broadcasters.
The incident at the nuclear operator came after the United States accused North Korea of a serious cyber-attack on Sony Pictures and vowed to respond proportionately.
Anti-nuclear activists in South Korea have also protested against the use of nuclear power.
Meanwhile, an Internet outage that cut North Korea from the Web ended after more than nine hours Tuesday with both the United States and China denying responsibility.
The outages, which began about 1 a.m. local time, shut down the Hermit Kingdom’s two government media outlets, the Korean Central News Agency and the Rodong Sinmun newspaper. Both were back online shortly before 11 a.m., with the Rodong Sinmun featuring photos of the country’s leader, Kim Jong Un, visiting a catfish farm.
China’s Xinhua news service on Tuesday quoted an unnamed Chinese official as saying that it may have been a simple systems failure.
Internet usage is notoriously restricted in North Korea, and all of its Web traffic is routed through China Unicom, the Chinese telecommunications giant. With only one point of access, North Korea’s Internet is vulnerable to “denial of service” attacks, and cyber-attackers.