Definition
OAuth vulnerabilities refer to security flaws in the implementation of OAuth 2.0, which can lead to unauthorized access, token theft, or session hijacking.How It Works
- 1Open Redirect Vulnerability: An attacker tricks a user into clicking a malicious link that redirects them after authorization.
- 2Token Theft via Referrer Headers: Sensitive tokens are exposed through the referrer header when redirected to an external site.
- 3CSRF on Callback Endpoints: Attackers exploit the lack of CSRF protections to perform actions on behalf of users.
- 4Insecure State Parameter Handling: The state parameter is not used or validated correctly, leading to attacks like CSRF.
- 5Authorization Code Interception: Attackers intercept the authorization code in transit and exchange it for a token.
Key Characteristics
- Misconfigured redirect URIs
- Lack of proper validation for state parameters
- Tokens exposed in URLs or headers
- Insufficient CSRF protections
Comparison
| Concept | Description |
|---|---|
| OAuth Vulnerabilities | Flaws in OAuth 2.0 implementation |
| XSS (Cross-Site Scripting) | Vulnerability allowing script injection attacks |
| SQL Injection | Vulnerability allowing SQL code execution via input |
Real-World Example
In 2018, a Facebook OAuth vulnerability (CVE-2018-16887) allowed attackers to gain unauthorized access to user accounts by exploiting an open redirect.Detection & Prevention
- Use PKCE (Proof Key for Code Exchange) to secure authorization codes.
- Employ tools like Burp Suite or OWASP ZAP to test for open redirects.
- Implement strict validation for redirect URIs and state parameters.
Common Misconceptions
- OAuth is inherently secure: Misconfigurations can make it vulnerable.
- State parameter is optional: It's crucial for CSRF protection.
- PKCE is only for mobile apps: PKCE is useful for any public client.