The U.S. military is known for planning for every possible scenario, and that includes taking out the regime of North Korean dictator Kim Jong Un.
Unfortunately for the U.S., North Korea got its hands on that very plan by after hacking into South Korea's Defense Integrated Data Center in September 2016, according to various reports.
Known as Operational Plan 5015 (OP5015), the scenario envisioned an operation in which the U.S. would essentially decapitate the North Korean regime at multiple levels. Unlike the Korean war of the 1950s which featured large armies on huge battlefields, OP5015 would use a lighter footprint by taking out targets with surgical air strikes, cyberwarfare and special operations forces. It would take out North Korean communications and command centers -- and conceivably Kim himself.
The plan takes a drastic turn from previous strategy toward the hermit nation, which focused predominantly on retaliating and mitigating North Korean aggression. Kim fields a massive army of 1.19 million active members, with another 7.7 million in reserve. A massive marauding force of North Korean soldiers steamrolling their way into Seoul has usually been the chief concern of South Korea and the international community, but it would appear the Kim regime has explored cyberwarfare as a cheap and effective way to engage adversaries.
North Korea is hardly the next Silicon Valley. Internet access is minimal and restricted, and much of the country has trouble simply keeping the lights on. But North Korea's cyberwarriors are more than capable. U.S. intelligence officials claimed North Korea-affiliated hackers were responsible for hacking Sony Pictures in 2014. A group known as "Guardians of Peace" leaked a trove of the company's internal data and demanded that Sony pull "The Interview," an upcoming comedy film about the assassination of Kim Jong Un, or it would engage in terrorist attacks at theaters showing the film.
North Korea denied involvement in the Sony incident, but its hackers have reportedly engaged in several other major cyberattacks ever since. North Korean hackers are alleged to have engaged in several ransomware schemes and were possibly behind the theft of $81 million from the Bangladesh central bank. They are currently known for targeting bitcoin exchanges in what some believe is an effort to use crytpo currency to skirt international sanctions.
Don't assume that OP5015 was the only plan for North Korea. The U.S. military typically fields multiple plans or options for a range of scenarios, so the North Koreans obtaining one of them might not be as bad as it sounds. What's more important is that the North Korean cyberwarriors have proven their capability going forward.