Red teaming is a way of testing security by acting like a real attacker. The goal is to see how well an organisation can stop, spot and respond to a red teaming attack. It looks at the full picture, not just technology, but also processes and people.

Penetration testing is different. It focuses on finding specific weaknesses in a system, application or network. Red team exercises go further, using the same tactics techniques and procedures ttps that a real threat actor might use. This can include technical, social and physical methods to test the whole security posture.

With more AI systems now in use, including generative AI and large language model tools, red teaming has expanded to test how these technologies can be tricked or misused.

From Military Practice to Cybersecurity

The term red team comes from the military, where the “red” side played the role of the enemy to test the “blue” side’s defences. In security today, red team is a group that acts like an attacker to find weaknesses.

Modern red teaming work can include testing computer systems, physical security and human behaviour. The aim is to protect sensitive information and prepare for real-world threats. It is especially valuable in complex organisations where weaknesses in different areas can be combined to create serious risks.

Red Teaming vs Penetration Testing

While both are part of security testing, they serve different purposes.

Penetration testing is narrower in scope, targeting specific systems or applications to confirm and document vulnerabilities. It provides a clear fix list for remediation. Red teaming, on the other hand, tests defences across multiple areas,  from technology to people, and focuses on how well blue teams respond to realistic, evolving attack scenarios.

How a Red Teaming Exercise Works

A teaming exercise is designed to feel as real as possible for the organisation being tested. While the exact plan changes from case to case, most follow several main stages.

It begins with careful planning, where objectives are agreed upon, such as trying to gain access to a network holding sensitive data or breaching a physical location. Rules of engagement are set to avoid damage or disruption to critical services, and boundaries are defined for what is in scope. Legal permissions are confirmed, and leadership is briefed on the aims.

Next comes reconnaissance. This involves gathering information from both digital and physical sources. Red teamers might carry out open source research using public records, social media or company websites, map the network to spot exposed services, observe physical security measures, and identify staff who might be targeted for social engineering attempts. This intelligence shapes the attack plan.

The attack simulation phase is where the exercise comes to life. Cyberattack methods such as exploiting software flaws, password cracking or planting malicious code may be combined with physical intrusions like tailgating into buildings or bypassing locks. Human-focused techniques, such as phishing emails, can be used to gather credentials before logging in remotely. 

Throughout this stage, tactics, techniques, and procedures are chosen to match real-world adversaries, and strategies are adapted based on the blue teams’ response.

The red team works towards its agreed objectives while avoiding detection. This might mean stealing a file containing sensitive information, taking control of a server or proving they could enter a restricted facility. The point is to measure what a real attacker could achieve without causing harm.

Finally, the team produces a detailed report explaining which methods worked, how defences reacted, and where gaps were found. Recommendations for improvement are given, often alongside a face-to-face debrief where the attack path is reviewed so lessons can be applied immediately.

The Role of Blue and Purple Teams

Blue teams are defenders, responsible for spotting suspicious activity, monitoring systems and responding to incidents. Purple teams act as a bridge between attackers and defenders, encouraging collaboration so that lessons from the attack are shared and defences can be strengthened without delay.

Red Teaming in the Age of AI

With generative AI and language model tools now in common use, the scope of security risks has widened. Red teamers test AI systems for vulnerabilities such as producing harmful or biased content, revealing sensitive information hidden in training data, or responding in ways outside the intended safety limits.

For example, prompt injection attacks can override restrictions, and testing can reveal if models leak private details or provide unsafe instructions. As AI becomes more embedded in daily operations, these risks require greater attention.

Choosing the Right Approach

The decision between penetration testing and full red teaming attack simulations depends on organisational maturity. Newer organisations may benefit more from penetration testing to find and fix known weaknesses before moving to more advanced testing. Mature organisations with established defences and response processes can gain more from red team exercises, which simulate complex, multi-step attacks.

Some organisations combine both, using penetration testing to identify and resolve vulnerabilities and red teaming to confirm overall readiness for real-world threats.

Benefits of Red Teaming

Red teaming tests technology, people and processes together, providing a more complete picture than standard audits. It can reveal weaknesses missed by other assessments, improve detection and incident response capabilities, and help build a proactive security culture.

Challenges to Consider

Running a realistic red team operation requires skilled testers and careful planning. If poorly managed, it can cause disruption. The rapid development of red teaming tools and attacker methods means organisations must regularly update their strategies to stay ahead.

Learning from the Results

The real value comes from applying what is learned. This might involve updating technical controls, refining incident response plans or providing staff training to improve awareness. Acting on these lessons reduces the chances of a successful future attack.

Conclusion

Red teaming is about more than finding weaknesses. It is about thinking like an attacker to test the full security posture. Whether applied to IT infrastructure, physical security or AI systems, it gives a realistic insight into defensive capability.

When combined with penetration testing, it offers a clearer view of readiness, helping to protect sensitive data and strengthen resilience against advanced threats.