It is unlikely that global warfare will occur due to super connectedness, but there is still a risk of conflict in many regions. In many parts of the world, civil war and endless terrorism are taking place, and the tools of warfare available to national and non-state actors are diversifying. Among them, cyber weapons which are much cheaper than other weapons and can be obtained easily by anyone, can put the critical infrastructures of a country at risk simultaneously. The characteristics of cyber threats are that surprise attack and destruction vary. The situation can change at any time if terrorists who are focused on mass destruction and extreme social turmoil understand the degree of destruction caused by new weapons. If the disgruntled terrorist group uses the lethal and destructive cyber skills properly, the size of the confusion can surpass that of traditional warfare. It is not just a hostile relationship. Just as a hacker group declares propaganda against the state and claims that they are legions, the notion of a regular army in cyberspace is slim, and the free and disordered internet provides a better environment for causing social disruption. Cyber space has significantly lowered the barriers to attacks by state and non-state actors, and the internet which is linked intricately, has become a new stage of action for terrorists. Even if they were not physically armed with nuclear weapons or missiles, weapons t process them were added to their hands. Cyber warfare with asymmetric and non-frontal characteristics is a battle of time and technology, and a battle of human perception. Until now, the border line between the countries was the criterion of national security. However in the digital world, the cyber countermeasures of the countries, the human resources, technology, and digital leadership to support them are the frontiers. In this paper, we propose a soft killing threat that is getting more and more sophisticated, an attack on infrastructure that is becoming more radical, the aspect of North Korea`s cyber provocation, and finally the direction of our military. The strengthening of cyber power can serve as a driving force to open a new horizon for military innovation, and it is necessary to make cyber security, which combines national security and growth power, a top priority for national defense reform.