Third-Party Integration Threats

Modern web applications rarely exist in isolation, integrating numerous third-party services that expand the threat landscape. Payment processors, while handling sensitive operations, create dependencies on external security. OAuth integrations for social login introduce complex token handling requirements. Analytics and marketing tools execute code with full access to page content. Each integration requires threat analysis for both functionality and security implications.

Supply chain attacks through compromised dependencies represent an escalating threat. NPM packages, Ruby gems, and Python packages power modern web development but can harbor malicious code. Even legitimate packages might be compromised through account takeover or build process infiltration. Dependency confusion attacks exploit naming similarities between public and private packages. Threat modeling must consider the entire dependency tree and update processes.

API integrations create bidirectional threats. Your application might be vulnerable to malicious responses from third-party APIs. Conversely, third-party webhooks calling your application could deliver attacks. Rate limiting, authentication, and data validation become critical at these integration points. Service degradation when third parties fail or become compromised requires planning through threat modeling.

Content delivery networks (CDNs) accelerate web applications but create new threat vectors. CDN compromise could serve malicious content to all users. Cache poisoning might persist malicious responses. Geographic distribution complicates incident response. Threat modeling must balance performance benefits against security risks and implement appropriate controls like subresource integrity.