Threat Modeling: Red and Blue (and Purple) Teams

 🔐 Threat Modeling: Red and Blue (and Purple) Teams 

1️⃣ Red Team – The Attackers 

• Simulate real-world attacks to test an organization’s security. 

• Emulate external or internal threat actors (hackers, malware, insiders). 

• Goal: Find vulnerabilities, gaps in detection, bypass controls. 

🔧 Activities: 

• Penetration testing 

• Social engineering (phishing, tailgating) 

• Exploit chains 

• Lateral movement simulation 

2️⃣ Blue Team – The Defenders 

• Responsible for defending the system. 

• Monitor, detect, and respond to threats. 

• Goal: Protect infrastructure, respond to incidents, strengthen detection. 

🔧 Activities: 

• Log monitoring (SIEM) 

• Intrusion detection/prevention 

• Security configuration management 

• Incident response & forensics 

 

3️⃣ Purple Team – The Bridge / “Security Striping” Concept 

• Not a separate team per se, but a collaborative function between red and blue teams. 

• Ensures continuous feedback between attackers and defenders. 

• Helps improve detection and response based on red team tactics. 

 

🧠 In Threat Modeling Context 

Threat modeling identifies and evaluates potential security risks in a system. The red/blue concept complements it: 

Role	In Threat Modeling
Red Team	Models how attackers might exploit a system.
Blue Team	Models how defenders can detect and block those attacks.
Purple Team	Ensures that what Red tests and Blue defends are aligned and improved together.

 

🧪 Real Example: EKS or Cloud Platform 

🔴 Red Team: 

• Try privilege escalation via misconfigured IAM roles 

• Exploit public S3 buckets or open security groups 

🔵 Blue Team: 

• Monitor CloudTrail and GuardDuty alerts 

• Validate logging and alerting for suspicious API calls 

🟣 Purple Collaboration: 

• Red shows a stealthy attack path 

• Blue tunes alerts in SIEM to detect it in the future 

• Repeat until detection is reliable 

 

🎯 Summary: Red, Blue, and "Strip" (Purple) 

Concept	Description
Red Team	Offensive – simulate adversaries, test weaknesses
Blue Team	Defensive – protect, detect, and respond to threats
Purple Team (strip)	Collaboration layer – ensures red & blue improve each other