Threat Modeling Process for Web Applications

Start web application threat modeling with a clear architecture diagram showing all components, data flows, and trust boundaries. Include client-side components, server-side applications, databases, caches, queues, and external integrations. Mark trust boundaries between browsers and servers, between different privilege levels, and at integration points. This visual representation guides systematic threat identification.

Apply STRIDE or other methodologies systematically to each component and data flow. For client-server communications, consider spoofing (forged requests), tampering (modified data in transit), and information disclosure (sensitive data exposure). For server components, analyze elevation of privilege and denial of service threats. Don't forget repudiation threats for audit-critical operations. Web-specific threat libraries accelerate this process.

Create abuse cases for major functionality. How might an attacker abuse the login process for username enumeration? Could the search feature be exploited for SQL injection? Might file upload enable arbitrary code execution? Could the payment process be manipulated to change prices? These scenario-based analyses reveal business logic vulnerabilities that component-based analysis might miss.

Prioritize identified threats based on exploitability and impact specific to web applications. Publicly exposed vulnerabilities face constant automated attacks, increasing likelihood. Client-side vulnerabilities might affect all users simultaneously. Data breaches trigger notification requirements and regulatory scrutiny. Service disruption immediately impacts revenue for e-commerce sites. Context-specific prioritization ensures relevant threats receive appropriate attention.

Web application threat modeling requires understanding both the unique challenges of web technologies and the specific threats facing your application. By systematically analyzing client-side and server-side components, session management, data handling, and third-party integrations, you can identify the threats that matter most. This focused approach ensures security efforts address real risks rather than theoretical vulnerabilities. As web technologies continue evolving, threat modeling provides the framework for understanding and addressing new security challenges in the ever-changing landscape of web application security.