Red Team vs. Purple Team: Which Does Your Organization Actually Need?

There’s a question that comes up constantly in conversations with security leaders: “Should we run a red team engagement or a purple team exercise?” It sounds like a straightforward either-or decision, but the real answer requires understanding what each approach actually does—and more importantly, what it doesn’t.

Too many organizations treat this as a maturity ladder. The assumption goes something like: you start with vulnerability scanning, graduate to penetration testing, then move to red teaming, and eventually arrive at purple teaming as the pinnacle. That framing is neat, intuitive, and mostly wrong.

The truth is that red and purple team engagements answer fundamentally different questions. Choosing between them isn’t about how sophisticated your security program is. It’s about what you need to know right now.

What Red Teams Actually Do

A red team engagement simulates a real adversary. The red team operates with a specific objective—gain access to a critical database, compromise a domain controller, exfiltrate sensitive files—and uses whatever combination of tactics, techniques, and procedures (TTPs) they can to achieve it. Social engineering, phishing, physical access attempts, custom tooling, living off the land (using legitimate tools already present in the environment). Everything is on the table.

The defining characteristic of a red team engagement is that your frontline defensive team doesn’t know it’s happening. A small group of senior stakeholders—sometimes called a “white team” or trusted agents—coordinates the engagement behind the scenes, but the SOC analysts and defenders operating day-to-day are in the dark. That’s the whole point. You’re testing your organization’s ability to detect and respond to a realistic attack under realistic conditions.

What you get out of a red team exercise is an honest picture of your real-world exposure. Not your theoretical exposure based on a list of CVEs, but what an actual motivated attacker could accomplish against your environment as it exists today—with all of its human factors, process gaps, and detection blind spots intact.

The downside? Red teams are adversarial by design. Your blue team (the defenders) learns that they missed something, but they don’t always learn why they missed it or how to fix the detection gap. The red team writes a report, the blue team reads the report, and there’s often a disconnect between what the attackers did and what the defenders can operationally change. That gap is where a lot of the value gets lost.

What Purple Teams Actually Do

A purple team exercise flips the model. Instead of simulating a covert adversary, the red team and blue team work together—often in the same room, sometimes literally shoulder to shoulder—walking through attack techniques in a controlled, collaborative way.

The red team executes a technique. The blue team watches their tools to see if it was detected. If it was, great—they validate the detection logic and move on. If it wasn’t, they work together in real time to figure out why. Was the telemetry missing? Was the detection rule misconfigured? Was the alert firing but nobody was looking at it?

This is where purple teaming gets powerful. It creates a tight feedback loop between offense and defense that accelerates your team’s ability to detect and respond to specific adversary behaviors. In our experience, organizations that run purple team exercises regularly see measurable improvements in detection coverage mapped to frameworks like MITRE ATT&CK. 

But purple teaming has its own limitation: it’s not realistic. Your defenders know the attack is coming. They’re watching for it. The exercise tells you whether your tools and processes can detect a technique—it doesn’t tell you whether your team would actually catch it in the wild on a Tuesday afternoon when they’re also dealing with three other tickets and a software rollout.

Choosing Based on What You Need to Learn

This is where the decision gets practical. The question isn’t “which is better?” It’s “what do we need to know?”

• You need to understand your real-world risk posture. If your board is asking “could an attacker actually get to our crown jewels?” or you’re trying to validate your security program against a realistic threat, a red team engagement gives you that answer with uncomfortable honesty.
• You need to improve detection and response capabilities. If you’ve invested in a SIEM, deployed EDR/XDR, built a SOC—and you want to know whether those investments are actually catching adversary behavior—a purple team exercise will systematically validate (or invalidate) your detection coverage and give your defenders hands-on experience tuning their tools.
• You’ve run a red team and the results were rough. This happens more often than people admit. If a red team walked through your environment without triggering a single alert, jumping straight into another red team engagement is probably not the move. A purple team exercise lets you methodically close the gaps before you test again.
• You’re preparing for a compliance audit or regulatory requirement. Some frameworks and regulators specifically call for adversary simulation. Understand what’s actually required—some mandate red team exercises (like TIBER-EU  and its evolution under DORA  in the European financial sector), while others can be satisfied with collaborative testing approaches.
• You want to build internal offensive security capability. Purple teaming is an exceptional training mechanism. Your blue team learns to think like attackers, and your organization develops institutional knowledge about adversary TTPs that persists long after the engagement ends.

The Case for Doing Both—Sequentially

The most effective approach we see in practice isn’t choosing one or the other permanently. It’s alternating them with purpose.

Run a purple team exercise to build and validate your detection capabilities. Give your team time to implement the improvements. Then run a red team engagement to see how those improvements hold up under realistic conditions. Take the lessons from the red team, feed them back into your next purple team cycle. Repeat.

This creates a continuous improvement loop that neither approach can achieve on its own. The purple team builds the muscle. The red team stress-tests it.

Where Organizations Get This Wrong

A few patterns we see repeatedly that undermine the value of these engagements:

• Treating red team reports as scorecards. A red team engagement isn’t a pass/fail test. If the red team achieved their objective, that’s not a failure—it’s information. The value is in understanding the attack path and what it reveals about your defenses.
• Running purple teams without action items. A purple team exercise that identifies detection gaps but doesn’t result in concrete, assigned remediation work is just an expensive demo. Every gap identified needs an owner and a timeline.
• Scoping engagements too narrowly. If you exclude social engineering, physical access, or cloud infrastructure from scope because those areas are “someone else’s responsibility,” you’re testing a version of your environment that doesn’t actually exist. Attackers don’t respect org charts.

Getting Started

Whether you need to understand your real-world exposure through adversary simulation or want to systematically strengthen your detection capabilities through collaborative testing, the key is being honest about what you’re trying to learn—and choosing the engagement that answers that specific question.

Plurilock’s Cyber Adversary Simulation and Response practice supports both red team and purple team engagements, along with the broader offensive security testing that makes them more effective. Our practitioners bring backgrounds in intelligence, military cyber operations, and enterprise security—and they’re focused on delivering outcomes that actually change your security posture, not just reports that gather dust.

If you’re unsure which approach fits your current situation, that conversation is worth having before you spend the budget. ■