What Is Red Teaming?

Red teaming is a structured security exercise that simulates how a real attacker would target your organization. Rather than looking for individual vulnerabilities, a red team works toward a specific objective, testing whether your people, processes, and technology can detect, contain, and respond to a realistic attack. Think of red-team exercises as ethical hacking.

Red teaming tests your organization’s assumptions about your security program, confirms that your investments are working as planned, and identifies weaknesses that a real attacker could exploit in the future.

Key Takeaways:

• In red teaming, ethical hackers simulate attacks to determine how well an organization can detect, isolate, and respond to a cyberattack.

• Organizations that tested their incident response plans saved an average of $2.66 million per breach, the largest single cost reducer identified in the IBM Cost of a Data Breach Report (2025).

• Red teaming complements existing security operations centers. The best results are achieved through red teaming when an organization already has baseline detection, investigation, and response capabilities. Internal and external red teams are different. Internal teams deliver ongoing, context-rich testing, and external teams deliver an attacker's perspective.

• Compliance regimes demonstrate that minimal security measures are in place, yet they fail to show whether those measures will withstand a determined attacker. Red teaming helps resolve this.

• The most productive red team engagements deliver evidence of existing vulnerabilities and actionable insights to improve detection, response, and resilience.

Red Teaming vs. Penetration Testing: What Is the Difference?

Penetration testing is done to find vulnerabilities within a particular scope set by the organization. Red teaming exercises evaluate whether a determined attacker can achieve their goals while your security tools and teams attempt to stop them.

Red Team Engagement

Who Is Red Teaming For?

Red teaming is designed for organizations that already have security operations in place and want to understand how those capabilities perform against advanced persistent threats. Organizations that cannot justify building or maintaining an internal red team can engage an external provider to assess a specific system, application, or business process. A focused engagement gives many of the same insights without the cost and commitment of maintaining an in-house capability.

Red teaming is not a substitute for foundational security controls. It is an attack simulation to test whether those controls work together when it matters, to prevent security incidents.

Organizations that have invested in advanced detection technology, defined investigative methodologies, and well-defined incident response processes will benefit the most from a red team assessment. This identifies vulnerabilities within an organization’s network that allow for undetected attack movement and response failures. 

If this framework is not in place, then findings become infinitely harder to act upon. If an organization cannot detect lateral movements or even execute an incident response process, it is better to develop these capabilities first. Red teaming works with existing security solutions; it cannot replace them. 

Internal vs. External Red Teams

Internal and external red teams have their own objectives. The choice of which to pick will largely depend on your requirements, testing frequency, and available resources. Some organizations use both.

The internal red team understands the business. As it gains more experience, it comes to know all the ins and outs of the organization's architecture and its most valuable assets.  This will help the red team emulate an attacker's actions, evaluate new systems, and challenge security decisions if they're in danger of becoming operational risks. 

The tradeoff is familiarity. Teams that know an environment well can develop blind spots or unconsciously avoid assumptions that deserve to be challenged.

External red teams bring a fresh perspective. They approach an organization the way a real attacker would, without prior knowledge of the environment or insight into what the blue team monitors. That independence often reveals weaknesses that internal teams may overlook and provides a realistic assessment of how an outside adversary would experience your defenses.

An external engagement comes to an end once the objectives have been met. What happens next depends on the organization. If the findings drive better detection, response, and remediation, the exercise has done its job.

A combination of both models can benefit most organizations. An external red team gives you an independent view of your security posture, while an internal team continues to test assumptions, validate changes, and improve SOCs over time.

How a Red Team Engagement Works: The Key Phases

A red team engagement is driven by objectives, not exhaustive testing. As the team learns more about the environment, it adapts its tactics just as a real attacker would.

A red team’s rules of engagement are as follows:

Reconnaissance

Every engagement begins by understanding the target. The red team gathers intelligence on the organization's attack surface, employees, third-party relationships, technology stack, and business processes to identify the most effective path to the engagement objective.

The Verizon 2025 Data Breach Investigations Report revealed that the human element is still a factor in most breaches, making people and business processes as important as technology during the reconnaissance phase. 

Attack Planning and Execution

The red team formulates a strategy in line with the engagement objectives and is informed by standards such as NIST, MITRE ATT&CK, and other frameworks. Throughout the exercise, the team adapts and evolves its strategy, exploring new paths to simulate attacks, and demonstrates which controls are effective, how well the business responds, and where detections fall short. 

Reporting and Remediation

The real value of red teaming lies in what the organization learns and changes after the engagement. The final report will outline the attack path, the techniques used, the control gaps, and ways to improve detection and response. The most effective programs treat the report as just the start of the process, prioritizing remediation and validating improvements before the next engagement.

Common Red Team Tactics

Red teams employ many of the same techniques that real attackers use to understand how well a company’s security tools perform under real-world attack conditions.

Network Penetration Testing

Network penetration testing simulates malicious actors’ behavior, as well as what they do once they have gained access to networks or systems. Red teams discover a vulnerability, gain initial access, and then move around and elevate privileges; ultimately determining whether adequate detection and containment measures are in place, and network security is effective.

Web Application Testing

Web applications and APIs are common attack paths. Red teams probe for authentication bypasses, injection flaws, broken access controls, and API vulnerabilities to see whether they can be combined into a realistic attack path.

Social Engineering

Social engineering and spear phishing tests are used to gauge how people will react to situations involving phishing e-mails, telephone calls, pretexting, and other attempts to obtain their credentials and other sensitive information. These simulated attacks help businesses see if their security training is working, if their SOCs are effective, and whether identity controls and response processes are doing their jobs in realistic situations. 

Physical Access Testing

Physical access testing assesses how effectively a firm protects its offices, data centers, and other sensitive locations. Red teams may try tailgating, badge cloning, and many other techniques that real adversaries use to test a company’s physical security measures, and see if they can withstand an attempted breach.

When Should You Invest in Red Teaming?

Red teaming is most valuable when an organization has baseline detection and response capabilities in place, and a significant event is either about to happen or has just finished. These circumstances present the most realistic scenarios for red teams to work.

After a significant architecture change

Cloud migrations and large infrastructure changes open up new attack vectors. Red teaming makes sure that security controls function as expected before an attacker can find and exploit them. 

Before a major audit

Compliance programs ensure that all necessary security controls are implemented. It does not validate if those controls can resist an active attack.

An organization could have good threat intelligence, be audited, and yet still be vulnerable to critical attack paths. Red teaming adds to compliance assurance and sees that security controls function under real-world adversarial scenarios rather than just a checklist.

Following a merger, acquisition, or major tool stack integration

A merger, acquisition, or integration of large tool stack integration comes with new infrastructure, legacy credentials, third-party access, and security assumptions. All of which increase the attack surface in hard-to-assess ways.

A red team engagement also helps businesses understand how new environments fit together, where trust boundaries have changed, and which attack paths now pose the greatest risk to sensitive data.

Earlier in system design

Finding weaknesses before systems go into production is almost always less costly than addressing them later.

Applying adversarial thinking during design and development helps teams identify security gaps before they become operational problems, reducing remediation effort while improving the resilience of the final system.

How Red Teaming Strengthens Security Operations

Red teaming shows the threat actors’ tactics, techniques, and procedures (TTPs), and how they move through your environment, where detections fail, how response performs, and what needs to improve. Those insights help security teams achieve reduced time from finding to fixing, fewer blind spots at next engagement, and detection coverage confirmed across the full stack before the next red team cycle

That process is harder when security data is spread across disconnected tools. ReliaQuest GreyMatter provides a unified detection and response layer across existing security investments, helping teams identify detection gaps, improve detection logic, and validate changes faster across the environment. 

How ReliaQuest Approaches Red Teaming

ReliaQuest's approach to red teaming exercises is based on one fundamental principle: red team early and often. Instead of looking for failures in existing controls, it focuses on making assumptions, validating decisions, and improving security before attackers discover and exploit vulnerabilities.

That philosophy extends beyond the security team. ReliaQuest's internal red team works closely with engineering, product, legal, finance, sales, and other business functions to understand how the organization operates and where the greatest risks exist. That context allows the team to emulate realistic attackers while helping the business make better security decisions.

Equally important is that the red team is seen as a partner rather than an adversary. The aim is to make sure security teams learn from the exercise, not just to prove that security measures are failing. When findings are shared and quickly acted upon, businesses strengthen detection and response and limit risk.

GreyMatter helps close that loop. As red team exercises uncover detection gaps, while GreyMatter provides the unified visibility that is needed to investigate findings, improve detection logic across the current security stack, and validate that those improvements are actually working before the next engagement.

For a deeper look at ReliaQuest's philosophy on building an effective red team program, read our companion thought leadership article.

Frequently Asked Questions