It looks like North Korea's "hermit nation" status has paid off in at least one way: the US was unable to infect the systems controlling centrifuges for North Korea's nuclear program, even after using a variant of the Stuxnet virus designed specifically for Korean systems. According to an exclusive report by Reuters, the National Security Agency led an effort in parallel to the one that went after Iran's nuclear program, but the agency failed to get its malware into North Korea's nuclear labs because they were so isolated—both in a geographic and communications sense.
Reuters' Joseph Menn cites an unnamed US intelligence official as saying the same team that developed Stuxnet—which was reportedly a joint US-Israeli development effort called "Olympic Games"—also developed a similar set of malware that would activate itself only when it encountered Korean language settings on the computers it infected.
Like Iran, North Korea used centrifuges obtained from the Pakistani scientist, A.Q. Khan, who led his own country's nuclear weapons effort. The P-2 centrifuges used by Iran were controlled by supervisory control and data acquisition (SCADA) systems from Siemens, with control software running on the Windows operating system. It was believed that North Korea used similar software because of the similarity between the two research efforts, so the STUXNET malware could in theory be used with minor modifications.