What is a Purple Team Exercise?

What Purple Team Exercises Test

Purple team exercises select specific attack techniques from MITRE ATT&CK relevant to the organization's threat environment, execute them in the production or representative environment with the defensive team's knowledge, and evaluate whether each technique generates the expected alert, is visible in available telemetry but not alerted, or is completely invisible to existing controls.

The collaborative model produces three outcomes for each tested technique: the technique was detected as expected — no action needed; the technique generated telemetry but no alert — a detection rule can be written and the gap is closed; or the technique generated no telemetry — a logging gap that must be addressed before detection is possible. Each outcome drives specific improvement actions.

Purple Team vs. Red Team

Red team operations are adversarial and evaluative — red team operators work independently, attempting to achieve objectives without defender awareness, producing an assessment of whether the organization can detect and respond to realistic attacks. Purple team exercises are collaborative and developmental — attackers and defenders work together with shared information to identify and close specific detection gaps. Both have value; they serve different purposes. Red teams evaluate overall capability; purple teams improve specific detection coverage.

Running a Purple Team Program

Mature purple team programs operate on a continuous cadence rather than as one-time events. A quarterly purple team cycle selects the top ATT&CK techniques relevant to current threat intelligence, executes them collaboratively, measures detection performance, writes new detection content for gaps identified, and validates in the subsequent cycle that new content works as intended. This creates a systematic improvement loop that translates threat intelligence into specific, validated detection improvements.

Purple Team for PE Portfolio Companies

For PE-backed companies without mature internal security operations teams, purple team exercises are most effectively delivered through MDR providers who conduct collaborative validation of their own detection content. An MDR provider that operates purple team exercises against their own detection content — and can demonstrate measured detection coverage improvement over time — provides higher confidence in detection capability than one whose capability claims are based solely on tool certifications and analyst credentials.

Real-World Example: Cloudskope Purple Team Reveals C2 Detection Gap

A purple team engagement for a PE-backed financial services company tested HTTPS-based C2 beaconing — specifically, Cobalt Strike Beacon traffic over port 443 with jittered intervals. The exercise revealed that while the organization's SIEM had correlation rules for known-bad C2 domains, it had no detection for behavioral beaconing patterns independent of domain reputation. The discovery enabled the security team to write and deploy behavioral detection rules that identified C2 activity through timing and volume patterns rather than domain blocklists — closing a gap that would have been exploitable by any attacker using infrastructure not already in threat intelligence feeds.