Proactive cyber defence means acting in anticipation to oppose an attack through cyber and cognitive domains. Proactive cyber defence can be understood as options between offensive and defensive measures. It includes interdicting, disrupting or deterring an attack or a threat's preparation to attack, either pre-emptively or in self-defence. Common methods include cyber deception, attribution, threat hunting and adversarial pursuit. The mission of the pre-emptive and proactive operations is to conduct aggressive interception and disruption activities against an adversary using: psychological operations, managed information dissemination, precision targeting, information warfare operations, computer network exploitation, and other active threat reduction measures. The proactive defense strategy is meant to improve information collection by stimulating reactions of the threat agents and to provide strike options as well as to enhance operational preparation of the real or virtual battlespace. Proactive cyber defence can be a measure for detecting and obtaining information before a cyber attack, or it can also be impending cyber operation and be determining the origin of an operation that involves launching a pre-emptive, preventive, or cyber counter-operation.
The offensive capacity includes the manipulation and/or disruption of networks and systems with the purpose of limiting or eliminating the adversary's operational capability. This capability can be required to guarantee one's freedom of action in the cyber domain. Cyber-attacks can be launched to repel an attack (active defence) or to support the operational action. Proactive cyber defence differs from active defence, meaning that it is pre-emptive (not waiting for an attack to occur). The distinction between active cyber defence and offensive cyber operations (OCO) is that the later requires legislative exceptions to undertake. Hence, offensive cyber capabilities may be developed in collaboration with industry and facilitated by private sector. But, these operations are often led by nation-states.