North Korean hackers breach South Korean submarine builder (again) - The Record

The target of the attack was Daewoo Shipbuilding & Marine Engineering (DSME), one of the country’s three primary shipbuilding companies—together with Hyundai and Samsung—and the only submarine builder.

Sources said that some of the stolen files included plans for a nuclear-powered submarine that DSME and the South Korean Navy had been working on for the past few years.