CWE-551: Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
Learn about CWE-551 (Incorrect Behavior Order: Authorization Before Parsing and Canonicalization), its security impact, exploitation methods, and prevention guidelines.
What is Incorrect Behavior Order: Authorization Before Parsing and Canonicalization?
• Overview: This vulnerability occurs when a web server checks for authorization before fully parsing and canonicalizing URLs. This can allow attackers to manipulate URL requests to bypass authorization mechanisms by exploiting discrepancies in URL interpretations.
• Exploitation Methods:
- Attackers can craft URLs using alternative representations, such as using dot-slash (e.g., /./) to refer to the current directory or other equivalent encodings, to bypass authorization checks.
- Common attack patterns involve inserting unexpected characters or sequences into URLs to confuse the server's authorization logic and gain unauthorized access to protected resources.
• Security Impact:
- Direct consequences include unauthorized access to restricted directories or files, leading to potential data breaches or exposure of sensitive information.
- Potential cascading effects could involve further exploitation of exposed data or services, leading to deeper penetration into the system.
- Business impact might include damage to reputation, financial losses, and legal implications due to non-compliance with data protection regulations.
• Prevention Guidelines:
- Specific code-level fixes include ensuring that URLs are fully parsed and canonicalized before any authorization checks are performed.
- Security best practices involve implementing a consistent URL parsing and canonicalization process across all components of the application.
- Recommended tools and frameworks include using established libraries and frameworks that handle URL canonicalization correctly and performing regular security reviews to identify and fix potential issues before deployment.
Technical Details
Likelihood of Exploit: Not specified
Affected Languages: Not specified
Affected Technologies: Not specified