FireEye suspects that the North Korea is responsible for a number of attacks against the South Korea relying a zero-day in the South most popular Word processor. The Hangul Word Processor is a proprietary software primarily used by government and public institutions in that country. The North Korea allegedly exploited it the an attack vector. The CVE-2015-6585 was fixed a few days ago by the developer of the Hangul word processor, Hancom. Experts from FireEye have warned that the attribution is not definitive, but the circumstance, the attack scenario and the target chosen by threat actor led the research to believe.”]
Source: https://securityaffairs.co/wordpress/40029/hacking/north-kore-0-day-hangul.html