Cybersecurity threats are growing every year, and businesses need stronger defences to protect their systems. Carrying out security assessments helps organisations find weaknesses before attackers can take advantage. Two of the most important ways to do this are pen testing and red teaming. While the two methods may sound similar, they have very different goals and approaches. Knowing the difference helps you choose the right security test for your organisation.

Quick Overview

The gap between penetration testing and red teaming comes down to purpose. Penetration testing focuses on finding as many issues as possible in a specific target system, while red teaming simulates a real attacker to see how well the security team and the blue team respond.

- Pen tests: Shorter tests are open to the security staff with the main aim of uncovering and fixing vulnerabilities.

- Red team assessments: Longer tests, carried out in secret, where the aim is to see how the organisation reacts to an attack.

Both are useful, but they deliver different types of insight.

What Is Penetration Testing?

Penetration testing, or pentesting, is about running controlled attacks against a defined target system to see how secure it is. Skilled pen testers use both automated tools and manual techniques to uncover weaknesses, such as outdated software, poor password security or application flaws.

A pen test always has a clear scope. The organisation and testers agree on what will be tested, for example, a website, cloud network, or mobile app. During the assessment, testers try to exploit flaws to show what impact they could have.

Unlike a red team engagement, penetration testing is not secret. The blue team usually knows the test is happening, so there is no focus on stealth. Instead, the aim is to give a full picture of vulnerabilities.

The output of a pen test includes:

- A list of vulnerabilities with risk levels.

- Proof of how they can be exploited.

- Clear advice on how to fix them.

This makes penetration testing useful for organisations building up their defences or needing proof of compliance. It goes further than vulnerability assessments, which only list issues without showing how they might be used in an attack.

What Is Red Teaming?

A red teaming exercise is much broader and more realistic. Instead of finding every possible flaw, red teamers aim to achieve a goal that reflects a real attack, such as accessing sensitive data or bypassing physical security.

A red team operation is usually carried out in secret, with only a few senior staff aware. This way, the security team and blue team are tested on how well they detect, respond and recover without any warning.

Red team assessments use tactics, techniques and procedures based on real attackers. These might include:

- Phishing staff for login details.

- Social engineering by phone or in person.

- Using stolen or cloned access cards.

- Deploying custom malware to stay hidden.

The goal is to stay undetected while moving through systems. This gives a clear view of how effective the organisation’s monitoring and incident response are in practice.

Because the test aims to copy advanced attackers, it usually runs for weeks or even months. The final report tells the story of the attack, including how the red team got in, what they achieved, what the defenders noticed, and what they missed.

Side-by-Side Comparison

Although both are types of security assessments, penetration testing and red teaming are very different in their aims and methods.

Penetration testing is focused on breadth. The purpose is to uncover as many vulnerabilities as possible in the agreed target system. It is structured, scoped, and visible to the organisation. The blue team usually knows the test is happening, so the emphasis is on identifying weaknesses rather than testing detection. Reports from pen tests contain detailed lists of issues, risk levels, and fixes.

A red team engagement takes a different approach. Instead of trying to find every possible flaw, the red team has a clear objective, such as gaining access to sensitive data or bypassing physical security. The exercise is carried out secretly, without the wider security team being informed. This allows the defenders to be tested on their ability to detect and respond in real time. The outcome is a narrative that explains how the attack unfolded, what was achieved, and how the organisation reacted.

The timelines reflect these differences. A pen test may take a few weeks, while a red team operation often lasts months, so the team can remain undetected and mimic a persistent attacker. Pen tests suit organisations building up their defences and needing regular checks. Red teaming is better for those with more mature security postures who want to test resilience against realistic threats.

Timelines, Effort and Resources

- Pen tests are short and controlled, often lasting three to six weeks. They are repeated regularly to maintain security hygiene.

- Red team operations need more planning and resources. They can take months and require specialists in digital, social and physical security.

This is why red teaming costs more and is usually reserved for organisations with stronger security postures that already carry out regular pen tests.

Attack Vectors in Practice

Penetration testing tends to focus on the technical side:

- Scanning a website for code flaws.

- Checking internal networks for outdated systems.

- Testing weak passwords or open services.

Red team engagement uses a wider set of attack vectors:

- Gathering open information on staff and systems.

- Sending phishing or vishing messages.

- Dropping infected devices in offices.

- Using malware to escalate privileges.

- Attempting physical access to buildings.

This makes the red team operation a better reflection of how a real attacker works.

Outputs and Learning Outcomes

The deliverables show the main difference:

- Pen tests provide a clear list of issues, their risk levels, and how to fix them. This helps improve the specific target system.

- Red team assessments explain how the attack was carried out, what the defenders saw, what they missed, and how their incident response can be improved.

Both add value, but one strengthens systems, while the other measures resilience.

Beyond the Basics: Blue, Red and Purple

- The red teamers copy attackers.

- The blue team defends and monitors.

- Purple teaming makes sure lessons learned are shared, so the defenders can improve quickly.

This model helps organisations get lasting value from their security tests.

Continuous and Automated Approaches

Traditional red team operations happen once every year or two. Newer methods, such as continuous automated red teaming (CART), now allow organisations to test more often, using automated tools that copy attacker behaviour. While these tools cannot replace human skill, they help provide regular assurance between larger engagements.

AI Red Teaming

Artificial intelligence creates new risks. AI red teaming is about testing how machine learning systems can be tricked. This might involve misleading prompts, poisoned data, or stress testing models to find weaknesses. These exercises also look at bias and ethics, not just technical flaws.

As more organisations use AI, these types of red team assessments will grow in importance.

Deciding Between Pen Tests and Red Teaming

- Choose a pen test if you want to know about technical weaknesses in a specific system.

- Choose a red team engagement if you already run regular pen tests and want to know how your whole organisation would cope with a real attack.

- The best approach is often a mix of both. Pen tests keep systems patched, while red team assessments make sure people and processes are ready for real threats.

FAQs

Is red teaming the same as black-box testing?

No. Black-box testing means testers have no system knowledge, but it is still limited in scope. A red team operation is broader and tests defenders as well as systems.

How long do red team engagements last?

They usually last weeks or months, giving time to stay hidden and copy real attackers.

Do pen tests include physical or social engineering?

Only if agreed. These methods are usually part of red team assessments.

What is the role of the blue team?

The blue team monitors systems and leads incident response. In red teaming, their real-time reaction is tested.

Can organisations do both penetration testing and red teaming?

Yes, and it is often best to combine them. Each test addresses a different layer of defence.

Conclusion

Both penetration testing and red teaming are vital parts of a strong security programme. Pen tests help improve specific systems by finding and fixing flaws. Red team exercises test how well the whole organisation holds up against a real attack, from detection to recovery.

Choosing the right approach depends on your goals. If you need to know where your technical weaknesses are, start with a pen test. If you want to see how your organisation responds under pressure, consider a red team assessment. Using both together gives the clearest picture of your strengths and weaknesses, helping you stay ahead of evolving threats.