Proactive cyber defense is focused on anticipating attacks and offensively protecting the targets (computers, systems, and networks) whenever an attack is launched. The intention is to aggressively disrupt the attack or the preparation for an attack by the threat vector. This renders the attack vector less effective, or capable of being repulsed with ease. Proactive cyber defense is arguably the best implementation of cybersecurity even though many organizations do not give it much thought. This approach foresees oncoming attacks and readies an arsenal of defense systems and strategies to disrupt these attacks or make them ineffective. Company assets are therefore seldom put at risk since the threat does not come into contact with them. Despite these advantages, many organizations opt to remain reactive or use operation cybersecurity due to a number of reasons, which we will outline next.