Purple Team: when to combine Red Team and Blue Team

Purple Team isn't a third team: it's a way of working where the red team (attacker) and the blue team (defender) collaborate in real time, instead of operating covertly and separately as in a classic Red Team. The goal shifts from "measure whether you'd catch us" to "improve your detection together, as fast as possible".

What Purple Teaming actually is

In a Purple Team exercise, the offensive team executes a specific technique — for example, a lateral movement technique via WMI — and, at that same moment, the defensive team checks live whether their SIEM or EDR caught it, which rule fired (or should have fired), and tunes detection right there. It's an iterative attack-observe-tune cycle, with both teams in the same room or call, technique by technique.

Purple Team vs covert Red Team: when to use each

A covert Red Team measures a genuine reaction, with no prior warning — it's the best way to assess the real state of your detection capability today. A Purple Team doesn't measure, it improves: it's collaborative and transparent, ideal when you already know you have detection gaps (from a previous Red Team, a real incident, or a recent infrastructure change) and want to close them efficiently, technique by technique, instead of waiting for the next covert exercise to check whether it worked.

When the collaborative model makes the most sense

Purple Team fits especially well when: you've just deployed a new SIEM/EDR and want to systematically validate its coverage against the MITRE ATT&CK framework; a previous Red Team revealed specific detection gaps you want to close with focus; you have a junior detection team and the goal is practical training as much as technical improvement; or the budget/time doesn't allow a full Red Team but does allow several sessions targeted at the highest-risk techniques for your sector.

FAQ

Does Purple Team take as long as a Red Team?

Usually less, and more predictably: being collaborative and focused on specific techniques (rather than a free-roaming objective to discover), a Purple Team session can be scoped to days rather than weeks, covering a specific set of MITRE ATT&CK TTPs.

Can we do a Red Team first and then a Purple Team?

That's the most common and recommended sequence: the Red Team reveals which techniques you failed to detect; the follow-up Purple Team works specifically on those techniques collaboratively until the gap is closed, with immediate validation that the fix works.