South Korean police has admitted that hackers from the North have hacked into networks at 160 South Korean firms and government agencies. In one case, blueprints for the wings of the Boeing F-15 were stolen from the computers of Korean Air Lines.
By 대한민국 국군 Republic of Korea Armed Forces (2013.8. 레드플래그 알래스카 훈련 Republic of Korea Air Force) [CC BY-SA 2.0], via Wikimedia Commons
The intrusions were detected in February and the breaches could be trace back to 2014.