Red Team / Blue Team

In military exercises, a red team plays the attacker and a blue team plays the defender. The exercise reveals weaknesses in strategy, communication, and response that classroom training cannot. Cybersecurity adopted this model because defending against theoretical attacks teaches far less than defending against real ones.

A red team is a group of skilled offensive security professionals who simulate advanced persistent threats (APTs). Unlike penetration testers who follow a defined scope and two-week timeline, red teams operate for weeks or months with minimal restrictions. They use the same tactics as real nation-state actors: phishing campaigns, supply chain compromise, persistence mechanisms, and slow lateral movement designed to evade detection.

The blue team is the defensive side: SOC analysts, incident responders, and detection engineers who detect and respond to the red team's attacks. The critical detail is that blue team often does not know the exercise is happening. Their response is being measured.

Microsoft's internal red team (DART) runs continuous adversary simulation against their own production infrastructure. Each exercise generates new detection rules and playbook updates. Google's red team has a permanent mandate to attack Google services from the perspective of a nation-state actor.

A purple team combines both, with red and blue working together to maximize learning. Red explains their techniques in real-time. Blue explains their gaps. Detection rules are written and tested during the exercise, not weeks after the report lands.