Red, Blue and Purple Teams Explained

Security teams borrow their color vocabulary from military exercises, where the red force plays the enemy and the blue force defends. In cybersecurity, the colors describe different roles and different kinds of exercises, and choosing the wrong one can waste time and money.

The red team

A red team emulates a specific adversary, often a real threat actor known to target the organization's sector, and pursues realistic objectives: reaching a sensitive system, stealing specific data or demonstrating control of critical operations.

Red team engagements differ from penetration tests in important ways:

• Objective, not coverage. A penetration test tries to find as many weaknesses as possible in a defined scope. A red team tries to achieve a goal, and uses whatever path works.
• Stealth. Red teams usually operate covertly, avoiding detection the way a real adversary would. Often only a small group of leaders knows the exercise is happening.
• Whole-organization scope. Red teams may combine technical attacks with phishing, phone-based social engineering and, where authorized, physical intrusion.
• Testing the defenders. The key question is not only "can we get in?" but "did anyone notice, and what did they do?"

A mature red team engagement is built around threat intelligence and frameworks such as MITRE ATT&CK, so the techniques used reflect how real adversaries operate.

The blue team

The blue team is the organization's defenders: the security operations center, incident responders, threat hunters and the engineers who maintain security tools. Their job is continuous: monitoring, detecting, investigating, responding and hardening.

Red team results are, in the end, a report card on the blue team's capabilities. That can create tension. The most effective organizations treat red team findings as learning, not blame.

The purple team

Purple teaming brings red and blue together in a collaborative exercise. Instead of the red team operating covertly and reporting weeks later, the two teams work openly:

1. The red team executes a specific technique, such as credential dumping or lateral movement using a remote management tool.
2. The blue team checks whether it was logged, whether an alert fired, and whether an analyst would have noticed.
3. If not, the teams identify why: missing logs, a detection rule that needs tuning, a tool that is not deployed where it should be.
4. The blue team fixes the gap, and the red team runs the technique again to confirm.

Over the course of an exercise, dozens of techniques can be tested and improved. The result is measurable detection improvement, not only a list of findings.

Which exercise is right for you?

The answer depends largely on detection maturity.

If you have limited logging and monitoring, a covert red team will likely succeed without being noticed, which confirms what you probably suspect but teaches little about how to improve. Start with purple teaming or a detection-focused assessment to build capability.

If you have a functioning security operations capability, purple teaming helps tune and extend it systematically, technique by technique.

If your defenses are mature and tested, a covert red team provides the most realistic test of whether people and processes hold up under real pressure, including escalation, communication and decision-making.

Many organizations cycle through all three: purple teaming to build capability, red teaming to test it, and continuous blue team improvement in between.

Planning a successful exercise

• Define objectives. What adversary, what goals, what questions should the exercise answer?
• Set rules of engagement. What is in scope, what is off limits, how will safety and business continuity be protected, and who can stop the exercise?
• Choose relevant techniques. Use threat intelligence about actors who target your sector.
• Plan the debrief. The value is in what defenders learn. Schedule time for detailed walkthroughs.
• Track improvements. Record detection gaps and follow them to closure, then retest.

Common mistakes

• Running a covert red team before basic logging and detection exist
• Treating results as a pass-or-fail grade for the security team
• Testing only technical controls, not escalation and response
• Failing to retest after fixing detection gaps

A sample purple team session

A half-day purple team session focused on credential theft and lateral movement might look like this:

1. The red team uses a common tool to extract credentials from a test workstation's memory. The blue team checks endpoint alerts: the technique was logged but did not trigger an alert. The detection rule is adjusted, the technique is repeated, and the alert fires.
2. The red team uses the stolen credentials to connect to a server with a remote management protocol. Network logs show the connection, but nothing flags it as unusual. The team writes a rule for administrative logins from workstations that do not normally make them.
3. The red team creates a scheduled task for persistence. It is detected and alerted correctly, which confirms an existing detection works.

At the end of the session, the team has two new detections, one validated detection, and a documented list of improvements, each tested against the real technique.

Frequently asked questions

Should the blue team know a red team exercise is happening? In a covert red team, usually only a small group knows, to test real response. In purple teaming, everyone knows; collaboration is the point.

How often should we run these exercises? Purple team sessions can run frequently, even monthly, as part of detection engineering. Covert red team engagements are typically less frequent, often annually, when defenses are mature enough to benefit.

How CDT can help

CDT plans and runs red, blue and purple team exercises built around real adversary behavior, and strengthens defenders through cyber hunt, managed security and hands-on training and exercises. Our CRIB cyber range lets teams rehearse safely, even in the field.