In early 2014, a contractor at credit-scoring company Korea Credit Bureau was arrested for loading up a USB key with personally identifiable information for some 20,000,000 people, about 40% of South Korea's population.
Shades of the Bradley/Chelsea Manning "Wikileaks" saga of three years earlier, in which decades of confidential US State Department cables were siphoned off.
Here's a sadly-still-relevant podcast from the Wikileaks incident, looking at the question, "How could this have happened?"