What Is a Red Team?

Organizations invest heavily in defensive security: firewalls, intrusion detection, employee training, and policies. But how do they know these defenses actually work?

A Red Team is a group of authorized security professionals who simulate real-world attacks to comprehensively test an organization's defenses. Unlike standard security assessments that focus on technical vulnerabilities, Red Teams take a holistic approach: they test technology, people, processes, and physical security simultaneously.

Red Teams operate with explicit authorization from organizational leadership. They're not attackers—they're defenders using offensive techniques to identify weaknesses before real attackers do.

The critical distinction: Red Teams have permission to attack. Everything they do is authorized, documented, and intended to improve security.

Red Team vs. Blue Team vs. Purple Team

Understanding the relationship between Teams:

Blue Team — The defenders. They protect systems, detect threats, respond to incidents, and improve security controls. Most security professionals are Blue Team.

Red Team — The attackers (authorized). They simulate real-world attacks, test defenses, and identify vulnerabilities. Red Teams help improve Blue Team capabilities.

Purple Team — Collaboration. Blue and Red teams work together, sharing findings and improving defenses collectively. Purple Team exercises combine offensive and defensive perspectives for maximum security improvement.

The relationship is collaborative. Red Team findings don't embarrass Blue Team—they provide data to improve defenses. Together, they strengthen organizational security.

Red Team Composition

Effective Red Teams are diverse, just like real threat actors. Team members specialize in different attack domains:

Technical Specialists

Network Penetration Testers — Exploit network vulnerabilities, perform lateral movement, escalate privileges, and demonstrate access to sensitive systems. They understand network protocols, routing, firewalls, and how to bypass them.

Application Security Testers — Find vulnerabilities in software applications: injection flaws, authentication bypasses, insecure APIs. They conduct code review and dynamic testing.

Malware Developers — Create custom malware for Red Team use, adapted to specific targets and objectives. They understand how malware persists, evades detection, and communicates with attackers.

Infrastructure Specialists — Set up command-and-control infrastructure, backdoors, and persistence mechanisms. They maintain operational security to avoid detection during exercises.

Non-Technical Specialists

Social Engineers — Master psychological manipulation. They craft phishing campaigns, conduct pretexting calls, and manipulate people into revealing information or taking actions that compromise security.

Physical Security Testers — Attempt to access secure facilities without authorization, test access controls, and identify physical vulnerabilities.

OSINT Specialists — Gather open-source intelligence about targets from public information. They analyze digital footprints, social media presence, and public records to understand targets.

Leadership

Red Team Lead — Plans engagements, coordinates team activities, manages scope and objectives, and serves as point of contact with organizational leadership.

Operations Lead — Manages day-to-day operations, ensures adherence to scope and rules of engagement, tracks activities, and maintains documentation.

This diverse composition allows Red Teams to attack from multiple angles simultaneously, simulating how real adversaries operate.

Red Team Engagement Phases

Red Team engagements are structured operations with distinct phases:

Phase 1: Scoping and Planning

Before attacking, Red Teams and organizational leadership define engagement parameters:

Objectives — What should the Red Team test? Which systems are in scope? What are the success criteria?

Scope — Which systems, networks, and facilities are included? Are supply chain partners in scope? Are remote employees included?

Rules of Engagement — What's permitted? What's explicitly forbidden? Are certain disruptive actions prohibited?

Timeline — How long is the engagement? What are key milestones?

Notification procedures — If the Red Team discovers critical vulnerabilities, who should be notified immediately?

Deconfliction — How do Red Team activities coordinate with ongoing security operations to avoid confusion or accidental disruption?

Clear scoping prevents misunderstandings and ensures Red Team activities serve organizational objectives.

Phase 2: Intelligence Gathering (Reconnaissance)

The Red Team researches the target extensively:

OSINT — Gathering publicly available information:

• Company websites and social media
• Employee LinkedIn profiles and job postings
• DNS records and network information
• Published documents and research
• Press releases and news articles
• GitHub repositories with source code
• Domain registration information

Social engineering reconnaissance — Calling employees pretending to be IT staff, vendors, or service providers to gather information or test awareness.

Physical reconnaissance — Visiting facilities to observe security measures, access controls, and personnel behavior.

Technical scanning — Identifying services, systems, and configurations visible from outside the network.

This phase can last weeks. Thorough reconnaissance dramatically increases attack success.

Phase 3: Initial Compromise

The Red Team attempts to gain initial access:

Spear phishing — Sending targeted emails to specific employees, crafted based on reconnaissance findings to appear legitimate. The goal is getting employees to click malicious links or download malware.

Exploit public-facing systems — Attempting to exploit vulnerabilities in web applications, email servers, or other externally accessible systems.

Supply chain compromise — If authorized, targeting vendors or partners that interact with the organization.

Physical intrusion — Attempting to gain access to secure facilities, plant devices, or interact with security personnel.

Credential compromise — Attempting to obtain valid credentials through various means.

Success at this stage is critical. Once inside, the Red Team can demonstrate deeper access.

Phase 4: Lateral Movement and Escalation

With initial access established, the Red Team expands:

Network mapping — Understanding the network topology, systems, and trust relationships.

Privilege escalation — Exploiting vulnerabilities or misconfigurations to escalate from user-level to administrative access.

Lateral movement — Compromising additional systems, moving through the network toward high-value targets.

Persistence — Installing backdoors and ensuring access persists if initial entry point is discovered.

Data access — Demonstrating access to sensitive data, intellectual property, or critical systems.

This phase demonstrates the impact of the initial compromise—how much damage an attacker could cause.

Phase 5: Reporting and Remediation

The Red Team documents findings and works with Blue Team and leadership:

Comprehensive reporting — Detailed documentation of:

• How they gained initial access
• Exploits and techniques used
• Systems and data accessed
• Persistence mechanisms installed
• Timeline of activities
• Detection gaps (what the Blue Team missed)
• Recommended remediation

Executive briefing — High-level summary for leadership explaining findings and business impact.

Detailed technical findings — For security teams to understand vulnerabilities and implement fixes.

Remediation support — Helping Blue Team understand vulnerabilities and recommend fixes.

Validation testing — After remediations are implemented, testing to confirm vulnerabilities are fixed.

Red Team Objectives

Red Team engagements pursue multiple objectives simultaneously:

Test Human Factors

Phishing susceptibility — What percentage of employees click malicious links? Who falls for social engineering?

Awareness assessment — Do employees recognize security threats? Would they report suspicious activity?

Policy compliance — Do employees follow security policies, or do they circumvent them for convenience?

Training effectiveness — Is security training actually changing employee behavior?

Understanding human vulnerabilities is critical because people remain the most exploitable security component.

Evaluate Technical Defenses

Network security — Can the Red Team bypass firewalls, IDS/IPS, or network segmentation?

Application security — Are there exploitable vulnerabilities in applications?

Endpoint protection — Can malware evade antivirus or endpoint detection systems?

Cloud security — Are cloud resources properly secured and configured?

Access controls — Can the Red Team bypass authentication or escalate privileges?

Technical testing reveals whether security tools are properly configured and effective.

Test Detection Capabilities

Alert response — When the Red Team triggers alerts, does the Blue Team detect and respond?

Forensics capability — Can the organization identify how the attack occurred?

Investigation speed — How quickly can the organization determine scope of compromise?

Attribution — Can they identify where the Red Team is operating from?

Organizations often discover that attacks go undetected for extended periods—weeks or months. Red Team testing reveals these gaps.

Assess Incident Response

Response procedures — Do incident response procedures actually work?

Team coordination — Can incident response teams coordinate effectively?

Communication — Is communication clear during incidents?

Decision-making — Can leadership make effective decisions under pressure?

Red Team attacks test incident response under realistic pressure.

Evaluate Physical Security

Facility access — Can the Red Team enter secure facilities?

Tailgating — Can they follow employees through access-controlled doors?

Device access — Can they access unattended computers or steal devices?

Environmental controls — Can they access sensitive areas due to physical security gaps?

Physical vulnerabilities often surprise organizations more than technical ones.

Test Supply Chain Security

Vendor access — Can attackers compromise vendors who have network access?

Third-party vulnerabilities — Are third-party systems properly integrated and secured?

Dependency risks — Are there risks from dependencies on external services?

Supply chain attacks (like SolarWinds) demonstrate this critical assessment area.

Red Team Operational Security (OPSEC)

Red Teams maintain operational security to avoid premature detection:

Covert operations — Most organizational employees don't know a Red Team exercise is occurring. This ensures responses are genuine, not influenced by knowledge of testing.

Low-noise techniques — Red Teams avoid triggering alerts unnecessarily. They move slowly and carefully through networks.

Encrypted communication — All Red Team communications use encryption to avoid detection.

Compartmentalization — Knowledge of the Red Team exercise is limited to leadership and incident response teams. This compartmentalization maintains test authenticity.

Activity tracking — Red Teams meticulously document all activities so findings can be reviewed and validated.

The goal is to simulate real attackers while ensuring organizational leadership can observe defensive response.

Red Team Value

Red Team engagements provide irreplaceable value:

Realistic Testing

Red Teams test defenses as real attackers would—using multiple vectors, multiple techniques, and persistence. Standard vulnerability scans might miss what a sophisticated Red Team discovers.

Prioritization Data

Red Team findings help organizations prioritize security investments. If Red Teams routinely gain initial access through phishing, employee training becomes a priority. If they access critical data without detection, monitoring improvements are needed.

Process Improvement

Red Teams don't just find vulnerabilities—they reveal process gaps. Incident response procedures that look good on paper might fail under real pressure.

Confidence Building

When Red Teams fail to compromise critical systems, it provides confidence that defenses are effective. When they succeed, it's actionable intelligence for improvement.

Culture Development

Red Team exercises reinforce that security is organization-wide responsibility. They demonstrate that defenses matter and test real capabilities.

Ethical Considerations

Red Team work is authorized offensive security, but strict ethics apply:

Explicit authorization — Red Teams only operate with documented, explicit authorization from organizational leadership.

Defined scope — Activities are strictly limited to defined scope. Testing outside scope is prohibited.

Minimized disruption — Red Teams avoid causing unnecessary operational disruption or data loss.

Documentation — All activities are documented and can be explained and justified.

Professional conduct — Red Teams act professionally and avoid activities that could be personal attacks or harassment.

Confidentiality — Red Team findings are confidential and shared only with authorized parties.

Red Teams operate at the intersection of offense and ethics, using realistic attack techniques within strict boundaries.

Exercise 1 — Write a safe engagement plan (high level)

Draft a one-page plan that includes:

• Scope (what is in/out)
• Rules of Engagement (constraints, safety)
• Success criteria
• Reporting deliverables

Question 1 — How is a Red Team engagement different from a standard pentest?

Next Lesson

Now that you understand how Red Teams conduct offensive security testing, it's time to explore the complete defensive cycle—Blue Team defensive operations and organizational protection strategies.

Next: Blue Team Defensive Operations