Applying Outside-In thinking to red team operations

Learn how to use Outside-In thinking strategy for red team operations.

Outside-in thinking is a strategy that focuses on viewing an organization, a system, or a problem from an external perspective such as customers, competitors, or attackers. It involves understanding how outsiders perceive an entity to identify vulnerabilities, opportunities, and areas for improvement.

In a business setting, this could mean understanding customer needs, market trends, and competitive threats before making strategic decisions. For example, a company looking to launch a new product might analyze customer expectations and industry disruptions before finalizing the product design. This ensures that decisions are made based on real-world demands rather than internal assumptions.

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From a red teaming perspective, the outside-in approach involves analyzing external attack surfaces first before engaging with internal security controls. Consider a company that assumes it is secure because it has strict internal policies and layered security defenses. A red team using outside-in thinking would start by investigating publicly available information, searching for leaked credentials, open ports, and exploitable web applications. They might discover a forgotten subdomain running outdated software or an employee’s exposed login credentials on the dark web—weaknesses that internal teams may have ignored. By thinking like an attacker, red teams can reveal security gaps that would otherwise go unnoticed. In fact, outside-in thinking is the foundation of adversary emulation and adversary simulation exercises.

This technique is closely linked to the 4 Ways of Seeing approach , particularly the perspective of "How attackers see us." The outside-in strategy forces organizations to step into the mindset of an adversary, identifying weaknesses from an external viewpoint rather than relying on an internal sense of security. The benefits of this method include realistic threat modeling, improved risk prioritization, and proactive security hardening. Instead of waiting for real attackers to find and exploit weaknesses, red teams help organizations address them in advance.

Red Team Notes
Outside-in thinking involves assessing security from an external attacker’s perspective. It is at the core of effective red teaming. Red teams use this approach, whether knowingly or unknowingly, to uncover hidden threats and attack paths that defenders might overlook. 

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