The Sacramento Bee reports about how North Korea was able turn itself into a global cyber power despite having such little internet access:

Initially, the most promising hackers were sent overseas, specifically to Shenyang, the largest city in northeast China and a one-hour bullet train ride from the North Korean border.

It was there, ensconced at the Chilbosan Hotel, a facility that is North Korea’s largest overseas investment, where early hackers practiced their skills. Shenyang has always been a hub of North Korean illicit activity, including trafficking in counterfeit products.

Over the years, the best hackers would fan out to other countries where North Koreans were permitted to live, Moriuchi said, sometimes associated with legitimate businesses like restaurants but also engaged in other activities. Seven countries known to have a physical presence of North Koreans, in addition to China, are India, Indonesia, Kenya, Malaysia, Mozambique, Nepal, and New Zealand. It is in those countries, perhaps behind legitimate businesses, that hackers may be operating.

Today, North Korea is believed to have “between 3,000 and 6,000 hackers trained in cyber operations,” says a report by the Congressional Research Service, titled North Korean Cyber Capabilities, dated Aug. 3.

Many of them are believed to be overseas. Successive U.S. administrations have sought to pressure allies to end trade and diplomatic relations with Pyongyang.

A short, but good, history of North Korean cyber operations and their major intrusions.