The Attack Surface Concept

Your application's attack surface encompasses all the points where an attacker could potentially interact with your system. Think of it like the exterior of a building—every door, window, vent, and even the walls themselves represent potential entry points. In web applications, the attack surface includes input fields, APIs, file uploads, URL parameters, cookies, and countless other interaction points.

Modern web applications have increasingly complex attack surfaces. A typical e-commerce site might have hundreds of input fields, dozens of API endpoints, multiple third-party integrations, and various user roles with different permissions. Each element adds to the attack surface, creating more opportunities for vulnerabilities. The OWASP Top 10 helps identify which parts of this surface are most commonly exploited and therefore deserve the most attention.