Testing OAuth2 Implementation Flaws

When to Use

• Assessing OAuth 2.0 authorization code flow for redirect URI validation weaknesses
• Testing OAuth client applications for CSRF protection (state parameter usage) and PKCE enforcement
• Evaluating token storage, transmission, and lifecycle management in OAuth implementations
• Testing scope escalation where clients request more permissions than authorized
• Assessing OpenID Connect implementations for ID token validation and nonce usage

Do not use without written authorization. OAuth testing may result in token theft or unauthorized access.

Prerequisites

• Written authorization specifying the OAuth provider and client applications in scope
• Test OAuth client registered with the authorization server
• Burp Suite Professional for intercepting OAuth redirects and token flows
• Python 3.10+ with requests and oauthlib libraries
• Browser developer tools for observing OAuth redirect chains
• Knowledge of the OAuth 2.0 grant types in use (authorization code, implicit, client credentials)