Every Chief Information Security Officer (CISO) knows that maintaining an organization’s cyber defenses is a constant battle, requiring regular proactive measures to stay ahead of threat actors. A red team exercise is a full-scope, real-world attack simulation that acts as the “diagnostic stress test” of an organization’s security immune system. Conducted by ethical hackers, it probes a company’s defenses (technology, people, and process) in a controlled but adversarial manner. The goal isn’t mere compliance or checklist completion; it’s to preemptively expose weaknesses, from unpatched systems to human errors, before a real attacker does—including highly advanced persistent threats (APTs) that blend social-engineering with stealthy malware. For a CISO, red teaming provides an unvarnished view of how an organization stands up to modern threats and where strategic reinforcements are needed.
Red teaming can be used to test assumptions and incident response, validate detection capabilities, and inform risk reduction initiatives. Across industries and geographies, different CISOs will have different objectives based on the unique threats they face. The defensive control stack they deploy and the strategies they employ are all influenced by the real adversaries that an organization faces and the tools, tactics, techniques, and procedures (TTPs) those adversaries use. Red team engagements simulate these threats and translate the technical offensive journey of an attacker into actionable insights, supporting investment decisions, informing board-level reporting, sharpening security operations center (SOC) performance, and ultimately bolstering an organization’s strategic resilience.
This is the first blog in a six-part red teaming series that I’ll be posting over the next couple of months. I wrote this series specifically for CISOs and security leaders, but it is applicable for any security professional considering leveraging the power of red teaming in their organization.
From a CISO’s perspective, red teaming is not an isolated technical drill—it is a core practice in offensive security programs that validates and strengthens an organization’s security posture. CISOs often employ red team exercises to see how their enterprise detection and response mechanisms hold up under a simulated crisis. Therefore, red teaming serves several critical functions in a mature security program to help both red and blue teams benchmark defensive readiness.
A red team exercise gives organizations an opportunity to safely experience a full-spectrum cyberattack leveraging multiple attack vectors tailored to top threats facing their respective industries. By simulating and sometimes emulating the TTPs of real adversaries, red teaming provides the closest approximation of how prepared a company truly is for an actual incident. A red team will covertly attempt to achieve specific goals, such as access sensitive data and disrupt operations, without being detected, thereby stress-testing cybersecurity defenses such as EDR, XDR, and zero-trust gateways under adversarial conditions. This “live-fire” drill often uncovers hidden vulnerabilities or attack paths identified through continuous vulnerability scanning and in-depth vulnerability assessment that routine scans or compliance audits miss.
CISOs often have assumptions about what their security controls and staff can handle (“Our new email filter will catch all phishing” or “Our incident response playbook covers ransomware”). Red teaming provides a reality check by actively attempting to bypass controls and procedures. It forces an organization to confront the question: “Are our defenses as effective as we think?” For example, if multi-factor authentication (MFA) is assumed to stop all unauthorized access, a red team might test that assumption with tactics like MFA fatigue attacks or adversary-in-the-middle phishing (one of the most common one of the most common phishing attacks exploited in modern IT security. exploited in modern IT security) to steal session tokens. Its success would reveal a gap in what was thought to be a strength. This process of assumption testing is invaluable; it illuminates systemic issues and blind spots in people, process, or technology that leadership might otherwise overlook.
A core purpose of red teaming is to allow an organization to evaluate its ability to detect, respond to, and recover from sophisticated attacks (purple teams would actually evaluate PDR metrics systematically over a wide range of TTPs). Unlike a standard penetration test, which often stops at finding vulnerabilities and exploiting them, a red team will operate covertly and stealthily over days, weeks, or months leveraging the MITRE ATT&CK framework to score detection coverage. This allows an organization or an incident responder to see if the SOC or blue team notices the presence of the red team. This tests the full incident response life cycle: Was the attack detected? How long did it take (mean time to detect, MTTD)? Did the team appropriately contain and eradicate the threat (mean time to remediate, MTTR)? Were escalation and communication procedures followed?
A red team exercise effectively measures an organization’s “immune response,” allowing security leaders to analyze and assess the outcomes of their teams. (Again, this analysis can be done by the testers in a purple team engagement.) Success is not just in the red team achieving its objectives but also in what is learned about the defensive team’s performance under pressure. Key metrics often emerge from these exercises. For instance, the results might reveal whether a breach was detected internally or by a third party and how long (in days) the red team “dwell time” was before detection. (Notably, Mandiant’s M-Trends 2024 report shows progress in this area; in 2023, the global median attacker dwell time fell to 10 days, down from 16 days in 2022, reflecting improved detection capabilities.) A well-run red team engagement will produce concrete data on detection gaps, and a good internal control group can measure response times, which a CISO can use to drive improvements.
Red teaming helps translate technical findings into business risk terms. By demonstrating the practical impact of certain vulnerabilities or process failures, it enables security leaders to prioritize what matters most. For example, a red team might show that a seemingly minor misconfiguration in the cloud could be chained with other weaknesses to cause a major data breach, turning an abstract risk into a vivid scenario for stakeholders. The exercise output is typically a report that classifies risks and recommends mitigations. This directly informs an organization’s risk register and reduction efforts. Additionally, it ensures that remediation efforts and security investments are focused on the most dangerous attack paths that attackers are likely to exploit, rather than theoretical issues. In this way, red teaming acts as a feedback loop for strategic risk management, continuously aligning a security program with the evolving threat landscape.
Overall, red teaming embodies a shift from reactive security (waiting for incidents to occur) to proactive security. It is a way to “train like you fight,” exercising an organization’s defenses regularly so that when a real incident happens, both technology and staff have essentially already survived similar scenarios. By uncovering weaknesses and prompting fixes, red teaming drives continuous improvement. It also has ancillary benefits: it raises security awareness among employees (they learn to be more vigilant if they know a phishing email could be a test). Mature organizations often institutionalize this by running frequent red team exercises and even continuous automated red teaming, often then leaning on collaborative purple team exercises to guide testing and collaboration and gather more insightful metrics.
One important distinction a CISO will note is the difference between red teaming and traditional penetration testing. While both are forms of ethical hacking, their scopes and objectives differ. Penetration testing is typically a narrowly scoped assessment of specific systems or applications for vulnerabilities, often performed with the knowledge of IT staff, to ensure those particular assets are secure. In contrast, red teaming is a broader, goal-oriented adversarial simulation: a red team mimics a real attacker by any means necessary, such as combining network exploits, social engineering, or physical intrusion, to achieve a goal, all while evading detection. Pen tests tend to be loud and announce every vulnerability found, whereas red teams are stealthy and look at the whole organization as an attacker would, often with only senior management aware it’s a drill. The aim of a red team is not to enumerate every bug but to test defenders and defense-in-depth as a whole.
Both pen tests and red teaming are important in a security strategy. In fact, they complement each other. Organizations with mature security programs employ both regular pen tests to harden specific assets and periodic red team exercises to evaluate holistic resilience. A CISO’s challenge is to integrate these efforts such that findings from any test feed improvements across people, process, and technology.
In many sectors, the value of red teaming has become so recognized that it’s mandated or strongly encouraged by regulators and industry standards. For instance, financial services in several regions must undergo intelligence-led red team exercises (e.g., the Bank of England’s CBEST or the European Central Bank’s TIBER-EU frameworks) to validate that critical assets like payment systems are well protected. These exercises are often conducted under strict oversight by regulators, aligning red team scenarios to real threat intelligence about adversaries targeting that sector. This regulatory push underscores a key point: from the boardroom’s perspective, red teaming is not just about finding holes—it’s about assuring stakeholders (regulators, customers, and the board) that the institution’s defenses work against high-end threats. Different industries face different threat profiles, and a CISO will tailor red team objectives to those mission-critical risks.
That’s a wrap on the first blog of our red teaming series! Tune in next week for my deep-dive into using red team outcomes for executive decision making.