Email remains a significant attack vector for modern cybercriminals, with the 2025 Verizon DBIR revealing that about 22% percent of the threat actors involve social engineering attacks, many of which begin with email.

While human behavior cannot be patched, the controls surrounding it can be pressure-tested. A mature red team identifies blind spots by simulating real adversaries: phishing employees, abusing OAuth tokens, and bypassing MFA, ideally before actual criminals do.

To counter these evolving threats, establishing a red team cybersecurity operation requires more than technical know-how. It demands a strategic, adversary-informed framework. This guide offers a structured approach to red teaming that rigorously tests both human and technical defenses.

In cybersecurity, a red team is a group of security professionals who simulate real-world attacks on an organization’s systems, networks, and people to find vulnerabilities before malicious hackers do.

They think and act like adversaries—using penetration testing, phishing, social engineering, and other attack techniques—to test how well the organization’s defenses hold up in practice.

A red team’s goal isn’t just to find weaknesses, but to challenge assumptions, reveal blind spots, and help improve security policies, tools, and training. They’re often paired with a blue team (the defenders) in what's called a red team–blue team exercise.

A red team objectively demonstrates how attackers can breach your defenses by independently testing your organization's people, processes, and technology through sustained, covert operations.

Unlike traditional penetration tests or defensive teams, red teams combine phishing, lateral movement, and persistence tactics to achieve business-impact goals. This approach clearly pinpoints where security controls fail, making vulnerabilities immediately visible and actionable.

Consequently, CISOs can translate technical risks into actionable, board-level metrics, such as detection speed and breach costs. Red team exercises validate existing security investments and help fulfill audit requirements.

Red teams are essential because they simulate realistic threats, including business email compromise, MFA fatigue phishing, and OAuth token abuse, which traditional methods might miss. Integrating these insights with AI-driven email security proactively strengthens defenses.

Having said that, here are some of the best practices to implement for setting up a red team cybersecurity operation:

Clearly defined objectives, a focused scope, and measurable success criteria transform red team engagements from theoretical exercises into actionable insights. Before your first simulated phishing email is sent, create a concise Goal and Scope Checklist outlining your objectives, targeted assets, email channels, collaboration platforms, success criteria, and executive sponsorship. Although this initial alignment may feel slow, it significantly reduces confusion and prevents extensive rework during the engagement.

Thoughtful planning in collaboration with internal stakeholders ensures that everyone remains on the same page throughout the exercise. Ultimately, defining clear goals upfront ensures the red team’s results deliver immediate, actionable value, empowering your security team to address vulnerabilities proactively and with precision.

The next practice includes translating each objective into attacker behaviors using the MITRE ATT&CK framework. Align scenarios with techniques such as Spear Phishing Link (T1566.002) or OAuth Token Abuse (T1528) for repeatable and comparable results. Incorporate broader frameworks, such as the Cyber Kill Chain, to maintain realism and business relevance.

Designate at least one scenario involving Microsoft 365 or Google Workspace email, as this is where most breaches originate. Define explicit success criteria in the Statement of Work, such as undetected exfiltration of a dummy invoice through a simulated vendor-compromise email.

Additionally, avoid common pitfalls like overly broad scope, neglecting third-party SaaS, or missing legal approvals. Clear objectives, focused scope, and proper authorization ensure impactful findings and actionable improvements.

To build an effective red team, select operators skilled in replicating current cyber threats and clearly articulating the business impact of each finding. Your team must demonstrate expertise across key attack surfaces, particularly email and cloud collaboration platforms. Social engineers craft realistic phishing and BEC messages to test user vigilance.

Specialists proficient in Microsoft 365 and Google Workspace simulate adversary tactics within collaborative environments. Developers create phishing kits, automate payload delivery, and develop malware that evades sandboxes.

Experts in email-header spoofing and domain impersonation utilize SPF, DKIM, and DMARC bypass methods, while engineers maintain discreet command-and-control channels. Together, these capabilities ensure your red team mirrors real-world attacker techniques, driving targeted defense improvements.

Technical talent alone isn't sufficient for a successful red team operation; soft skills such as stealth, curiosity, and storytelling are equally critical. These skills help executives clearly see the real-world impact of overlooked threats.

Diverse backgrounds among team members foster creativity, helping anticipate unexpected attacks and supply-chain vulnerabilities. Thoughtful selection of tools, prioritizing familiarity and low detection risk, ensures realistic simulations without triggering alarms.

Core team roles typically include an email security specialist to assess SPF, DKIM, and DMARC results; a blue-team liaison who coordinates operations and response; and a report writer skilled in translating technical details into meaningful business insights. Also, selectively outsourcing niche expertise complements internal capabilities, providing clear and actionable results rather than simply highlighting vulnerabilities without context.

Establishing clear Rules of Engagement (ROE) and structured communication protocols ensures your red team operates aggressively yet safely, without risking unintended consequences. A robust ROE is a time-bound, mutually agreed contract defining the precise scope and limits of the engagement.

Create it before reconnaissance starts, detailing operating hours, blackout dates, permitted techniques like phishing or domain spoofing, explicitly off-limits systems, and legal considerations. Include a designated 24/7 escalation contact authorized to stop activities immediately. Circulate and secure stakeholder approval, using industry-standard frameworks for guidance.

The finalized, signed document provides critical legal protection, operational clarity, and a reliable audit trail, ensuring your red team remains effective without encountering unnecessary risks or regulatory complications.

Effective red team operations depend on secure, structured communication. Establish encrypted channels like Signal, Matrix, or secure Slack for real-time coordination. Post daily situation reports summarizing achieved objectives, detections, and unexpected impacts. Define a single-word safeword to immediately halt activities if real incidents or critical systems are impacted.

Also, configure mailbox rules to route simulated threats into dedicated quarantine folders, preserving blue-team metrics. Pre-authorize domain-spoofing by updating SPF and DKIM records, protecting email reputation. Conclude engagements with encrypted debrief calls to review insights and promptly initiate remediation actions. Remember, clear, continuous, and secure communication ensures operations remain effective, legally compliant, and aligned with actionable improvements.

Red team exercises deliver measurable value only when findings translate directly into improved defenses. Effective integration follows a structured process: capturing data, conducting root-cause analysis, prioritizing issues, performing remediation, and validating through re-testing. Immediately after an exercise, map each tactic used to MITRE ATT&CK, clearly identifying defensive gaps.

Translate findings into an executive-friendly remediation matrix: quick wins (e.g., enabling SPF alignment) completed within 30 days; medium-priority fixes (such as tightening mailbox-forwarding rules) within 90 days; and strategic initiatives (DMARC enforcement) extending beyond 90 days.

Next, link each issue explicitly to email security gaps, emphasizing real threats rather than theoretical risks. Joint debriefs involving IT, Legal, and Compliance ensure balanced attention, driving continuous improvement and measurable progress in subsequent exercises.

Effective red teams deliver measurable improvements in threat detection, rapid containment, and stronger defenses. Prioritize outcome-focused metrics rather than counting exploits. The key indicators in this case include detection lag (time from payload delivery to initial alert), mean time to contain threats, objective completion rate (percentage of blocked red team goals), and prevented business impact in financial terms.

Enhance measurement with email-specific metrics like phishing detection rates, accuracy of business email compromise (BEC) prevention, and false-positive reductions, demonstrating cohesive defense through user awareness, secure email gateway configurations, and behavioral AI.

After engagements, update threat models, refine MITRE ATT&CK mappings, retrain staff, and adjust policies accordingly. Continuous, measurement-driven red team testing transitions your security program from reactive assessments to proactive, evidence-based resilience.

Red-team exercises deliver significant value, but turning findings into measurable security improvements demands precision and actionable insights. Abnormal transforms your red-team operations by integrating advanced behavioral AI and real-time analytics, enabling teams to emulate realistic adversary tactics and precisely measure blue-team responsiveness. Rather than static tests, Abnormal facilitates dynamic scenarios tailored to evolving email threats, ranging from sophisticated phishing to OAuth abuse, ensuring your defensive controls continuously improve. Each exercise generates clear, actionable feedback that directly enhances email security policies, accelerates threat detection, and reduces risk.

By leveraging Abnormal’s capabilities, organizations achieve a proactive security posture, closing detection gaps before real attackers exploit them. Experience firsthand how Abnormal supercharges your red-team strategy, making exercises more realistic, results more meaningful, and security outcomes more impactful. Ready to take your cybersecurity to the next level? Book a personalized demo today.