Over a two year span, North Korea has nearly doubled the size of its cyber war unit from 3000 to 5900 personnel. The unit under the General Bureau of Reconnaissance operates with 1200 professional hackers through overseas bases (i.e. China) to attack various public and private entities, mostly in South Korea. In response to increased North Korean activity, South Korea has increased is cybersecurity budget to train and recruit hackers for its cyber command.
Source: SecurityWeek