The Rise of Purple Teaming: Bridging the Gap Between Offense and Defense

Wylie Bayes

• 3 min read

Historically, the relationship between offensive security (Red Team) and defensive security (Blue Team) has been highly adversarial.

The Red Team spends a month sneaking around the network, popping domain controllers, and feeling incredibly smart. At the end of the engagement, they drop a 150-page PDF on the Blue Team's desk outlining every failure, pack up, and leave. The Blue Team, already overworked, feels demoralized and defensive. Six months later, the cycle repeats, and often, the exact same vulnerabilities are exploited.

This siloed approach is broken. To actually improve an organization's security posture, the industry is rapidly shifting toward a collaborative methodology known as Purple Teaming.

What is Purple Teaming?

Purple Teaming is not necessarily a separate team of people you hire; it is a mindset and a methodology. It is the intentional, structured collaboration between the attackers and the defenders during an active simulation.

Instead of hiding from the Blue Team, the Red Team sits right next to them (physically or virtually). They execute a specific attack technique, and immediately turn to the Blue Team and ask: "Did you see that?"

If the Blue Team didn't see it, they figure out why, write a detection rule on the spot, and have the Red Team run the exact same attack again to verify the new alert works.

The Purple Team Exercise: Step-by-Step

A successful Purple Team exercise is highly structured. Here is how a typical engagement flows:

1. Preparation and Threat Modeling

Both teams agree on the scope. They often use the MITRE ATT&CK Framework as their common language. For example, they might decide to focus strictly on testing defenses against "Credential Access" (Tactic TA0006). They select 5 specific techniques to execute, such as LSASS Memory Dumping and Kerberoasting.

2. Execution (The Red Action)

The Red Team executes the first technique—let's say dumping LSASS memory using a custom PowerShell script. They note the exact timestamp, the source IP, and the target hostname.

3. Detection (The Blue Reaction)

The Blue Team looks at their SIEM, EDR, and network logs.

  • Did an alert fire?
  • If not, is the raw telemetry data (Event ID 4688 or EDR process memory logs) even making it to the SIEM?

4. Tuning and Remediation (The Purple Collaboration)

If the data is there but no alert fired, the Blue Team writes a new KQL or SPL query in the SIEM to detect the specific PowerShell behavior.

5. Re-Execution

The Red Team runs the attack again. This time, the Blue Team's dashboard lights up red. Success! They have successfully closed a detection gap. They document the fix and move on to the next technique on the list.

The Tools of the Trade

Purple Teaming relies heavily on automation and tracking frameworks.

  • Atomic Red Team: Developed by Red Canary, this is an open-source library of simple, highly specific tests mapped directly to the MITRE ATT&CK framework. It allows defenders to easily simulate attacks without needing to be master malware developers.
  • VECTR: A fantastic tracking tool used to document Purple Team exercises. It tracks which techniques were executed, whether they were blocked, logged, or alerted, and generates incredible metrics for management.
  • Caldera / Prelude: Automated adversary emulation platforms that can chain multiple techniques together to simulate complex, multi-stage attacks.

The ROI of Purple Teaming

The return on investment for a Purple Team exercise is massive.

  1. Instant Value: Organizations don't have to wait a month for a report to start fixing things. Defenses are improved in real-time.
  2. Tool Validation: It proves whether the expensive EDR and SIEM platforms you purchased are actually configured correctly and generating value.
  3. Culture Shift: It breaks down the toxic "us vs. them" mentality. The Red Team learns how difficult defense truly is, and the Blue Team learns the intricate mechanics of modern malware. The teams walk away with immense mutual respect.

Conclusion

If your organization is still treating penetration testing as a secretive, adversarial game of "Gotcha!", you are wasting budget. By bringing offense and defense to the same table, Purple Teaming transforms security assessments from a compliance checklist into a rapid, highly effective training ground.