What is an OAuth redirect_uri bypass?

An OAuth redirect_uri bypass is a vulnerability where an attacker manipulates the redirect_uri parameter to make the authorization server send the authorization code to an attacker-controlled URL. Techniques include path traversal, subdomain confusion, regex bypasses, and open redirect chaining.

What is a PKCE downgrade attack?

A PKCE (Proof Key for Code Exchange) downgrade attack occurs when an authorization server does not enforce PKCE, allowing an attacker to obtain authorization codes without the corresponding code_verifier. This enables authorization code interception attacks.

How does OAuth CSRF work?

OAuth CSRF occurs when the state parameter is missing or not validated. An attacker can craft a malicious OAuth authorization URL and trick a victim into visiting it, causing the victim's browser to complete an OAuth flow that links the attacker's account or leaks an authorization code.

Also available inAPI Security Studio →— OWASP API Top 10 & GraphQL in one place.

OAuth / OIDC Attack Wizard

Test OAuth 2.0 and OIDC implementations for security vulnerabilities. Enter your target's OAuth configuration to generate 27+ categorized attack payloads covering redirect_uri bypass, PKCE downgrade, state CSRF, token leakage, implicit flow issues, and OIDC-specific attacks. For authorized testing only.

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Authorization URL

Token URL

Redirect URI (registered)

Client ID

Scope

Response Type

Attack Surface Summary

Redirect URI Bypass11 variants

PKCE Attacks4 variants

State / CSRF3 variants

Token Leakage4 variants

Implicit Flow2 variants

OIDC-Specific3 variants

For authorized penetration testing and security research only. Never test against systems you do not own or have explicit permission to test.

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