An active defense is the use of offensive actions to outmaneuver an adversary and make an attack more difficult to carry out. Slowing down or derailing the attacker so they cannot advance or complete their attack increases the probability that they will make a mistake and expose their presence or reveal their attack vector.
While the term active defense is often associated with military applications and protecting critical infrastructure and key resources (CIKR), it also applies to information technology (IT) security. In cybersecurity, an active defense raises the financial cost of an attack in terms of wasting the attacker's processing power and time. Applying offense-driven strategies is critical to being able to detect and stop not only external threat actors, but also insiders and attackers with varying motivations including ransomware, extortion
An active defense complements offense-driven actions and allows an organization to proactively detect and derail attacks early and gather the threat intelligence required to understand the attack and prevent a similar recurrence. Sometimes active defense includes striking back at an attacker, but this is normally reserved for military and law enforcement that have the resources and authority to confirm attribution and take appropriate action.
Deception technology can be used to detect an attacker early on in the attack cycle by obfuscating the attack surface with realistic device decoys and attractive digital bait. Misdirection can trick the attacker into engaging and lead them to believe they are escalating their attack, when in fact, they are wasting their time and processing power and providing the defender with counterintelligence. The forensic information gathered through an active defense can then be applied to defense strategies and stop a live attack, identify forensic artifacts and expedite incident response to prevent the attack from resurfacing.