North Korea’s ongoing cyberwar with Sony Pictures and the US might be stealing most of the headlines this Christmas, but that hasn’t spared its near-neighbor South Korea from a hacking scandal of its own.

Reports at the weekend suggested one of the country’s nuclear power stations may have been compromised by hackers, though the operator of the plant in question stressed that no critical data was leaked.

According to South Korea’s Yonhap News Agency, the hacker or hackers were able to access various “blueprints, floor maps and other data” during the attack. A Twitter account called “president of anti-nuclear reactor group” has made four postings of leaked data showing internal designs and manuals of the Gori-2 and Wolsong-1 nuclear reactors run by Korea Hydro and Nuclear Power Co. (KHNP), since the attack took place on December 15. The hackers have since threatened to release further data unless the reactors are shut down.

KHNP told Yonhap that no critical information was leaked, and that none of the stolen data undermines the reactor’s safety. It also played down fears of any further cyberattacks against it, saying that its systems are protected because they’re all housed in an internal network that’s not connected to the Internet. KHNP is erring on the side of caution however – following Sunday’s report it announced plans to conduct a two-day drill to test its resilience to digital attacks, which kicked off on Monday.

It’s not known if the attack bears any relation to the ongoing cyberwar between Sony Pictures, the US and North Korea. South Korea’s government has said it’s handling the incident with “extreme care” but it hasn’t yet fingered any culprits. One KHNP official told Reuters the attack appeared to be carried out by “elements who want to cause social unrest,” but refused to elaborate further.

photo credit: C.M. Keiner via photopin cc