TL;DR: Purple team exercises run specific adversary techniques against your environment while defenders watch in real time — converting detection gaps from theoretical concerns into measurable, fixable issues. The output is a quantified MITRE ATT&CK coverage map and a prioritized list of detection engineering improvements. It is the most effective way to spend a security improvement budget if you already have centralized logging.
The Problem with Traditional Red Team Engagements
Red team engagements are a critical component of a mature security program. They answer the question "what can an attacker accomplish in our environment?" with precision and realism that no compliance checklist or vulnerability scanner can match. But they have a structural limitation when the goal is improving detection coverage rather than simply discovering vulnerabilities.
The traditional red team engagement model operates in isolation from the blue team. The red team conducts the engagement covertly — the blue team is unaware of when it is occurring and which techniques are being used. The red team delivers a report weeks after the engagement concludes. The blue team reviews the report, identifies techniques that were not detected, and then attempts to write detection rules from written descriptions of activity that occurred in the past, in an environment that has since changed.
This feedback loop is too slow and too indirect to efficiently drive detection improvement. The red team knows exactly which events were generated when a specific technique was executed. That knowledge is not captured in a written report and is largely lost. The blue team is left reverse-engineering detection logic without the real-time data that would make rule writing straightforward.
Purple teaming solves this structural problem by collapsing the feedback loop to near-zero latency.
How a Purple Team Session Actually Works
A purple team exercise is a collaborative, transparent engagement where red team operators execute specific adversary techniques while blue team analysts monitor their SIEM, EDR, and network monitoring tools in real time. The session is structured around a technique-by-technique workflow:
- Technique selection: Before the session, the red and blue teams agree on a prioritized list of MITRE ATT&CK techniques to test, typically selected based on threat intelligence (which techniques are used by threat actors targeting your industry) and known defensive gaps.
- Execution: The red team executes the technique in the target environment, typically on a designated test system that has been confirmed to have the same monitoring agent configuration as production endpoints.
- Detection check: The blue team checks whether the execution generated any alerts or log events in the SIEM or EDR within a defined window (typically 5-10 minutes). Both teams examine the raw logs together.
- Detection rule development: If no alert was generated, the blue team writes a detection rule on the spot, using the actual log events generated by the just-executed technique as the basis for the rule logic.
- Validation re-execution: The red team re-executes the technique to confirm that the new rule generates an alert. The detection coverage is confirmed, not assumed.
- Coverage mapping: Each tested technique is marked as detected, not detected, or detected with tuning on the ATT&CK Navigator heatmap. The cumulative coverage score improves with each session.
A well-structured purple team session covers 15-30 techniques per day, depending on complexity. Over a multi-day engagement, an organization can measurably improve its ATT&CK coverage across an entire tactic category.
Pentest vs. Red Team vs. Purple Team: What Each Delivers
| Exercise Type | Primary Question Answered | Blue Team Role | Output | Best Used For |
|---|---|---|---|---|
| Penetration Test | What vulnerabilities exist and can be exploited? | Not involved (assessment is of attack surface) | Findings report with remediation recommendations | Validating security controls, compliance requirements, pre-deployment testing |
| Red Team Engagement | What can a sophisticated attacker achieve in our environment? | Unaware — tests real detection and response | Narrative attack chain, detection gap analysis, recommendations | Realistic threat simulation, testing IR procedures, executive-level assurance |
| Purple Team Exercise | Does our detection stack catch these specific techniques? | Actively engaged — writing and validating rules in real time | ATT&CK coverage heatmap, validated detection rules, measurable improvement metrics | SIEM/EDR tuning, detection engineering uplift, SOC capability improvement |
These exercises are complementary, not alternatives. A penetration test identifies the vulnerabilities. A red team engagement tests whether your defenses would stop a determined adversary. A purple team exercise systematically improves the detection coverage that makes your defenses effective. Most mature security programs use all three at different cadences.
The Maturity Prerequisites
Purple teaming requires functional visibility infrastructure to add value. Specifically:
- Centralized logging: Endpoint logs, authentication events, network flow data, and DNS queries must be collected in a central platform. Without centralized logging, the blue team has no single place to check for detection events.
- Working SIEM or EDR: The SIEM must be operational and processing logs in near-real-time. The EDR must be deployed consistently across endpoints, including the test systems used in the exercise.
- Detection engineering capacity: Someone on the blue team must be capable of writing detection rules — whether Sigma rules for a SIEM, custom EDR queries, or equivalent. Purple teaming is a detection engineering exercise; the output is rules, not just findings.
Organizations that lack centralized logging will benefit more from investing in their logging and SIEM infrastructure first, then running purple team exercises once the foundation exists. Attempting purple teaming on a logging foundation that has significant gaps produces an inaccurate picture of detection coverage — gaps in coverage may be attributed to missing detection rules when they actually result from missing log sources.
What Organizations Gain from Purple Teaming
The tangible outputs of a well-executed purple team program go beyond the specific detection rules written during sessions. Organizations gain:
- Quantified ATT&CK coverage: A documented, validated percentage of MITRE ATT&CK techniques that generate detectable alerts, broken down by tactic category. This is a defensible metric that can be presented to a CISO, board, or audit committee.
- Justified SIEM tuning budget: When detection rule gaps are mapped to specific techniques used by known threat groups targeting your industry, the business case for SIEM engineering resources becomes concrete and prioritized.
- Realistic SOC and MDR capability assessment: If your SOC or MDR provider is observing the same monitoring infrastructure during the exercise, the session also assesses whether alerts that are generated are being acted on within an acceptable time window.
- Validated detection rule library: Every rule written during a purple team session has been validated against real technique execution. This is fundamentally different from rules written from theoretical documentation, which often generate false positives or miss the actual events of interest.
- Team capability development: Blue team analysts develop threat-informed detection engineering skills through hands-on collaboration with experienced red team operators. The knowledge transfer from these sessions compounds over time.
Measurement matters: If you cannot measure your detection coverage, you cannot improve it systematically. A MITRE ATT&CK heatmap produced from validated purple team testing is one of the most credible security metrics a security team can bring to an executive conversation. "We detect X% of techniques used by the threat groups targeting our sector, up from Y% six months ago" is a meaningful security posture statement. "We have EDR deployed on all endpoints" is not.
Lorikeet Security's offensive security team conducts purple team exercises structured around the threat intelligence most relevant to your industry, with blue team knowledge transfer embedded throughout the engagement. Contact us to discuss how a purple team program fits your current security maturity and detection infrastructure.
Measure and Improve Your Detection Coverage with Purple Teaming
Lorikeet Security designs and delivers purple team exercises that produce validated MITRE ATT&CK coverage maps, working detection rules, and measurable security posture improvement.
