CRLF Injection Scanner
Tests for carriage return line feed injection in HTTP headers.
What is CRLF Injection?
CRLF injection specifically exploits the carriage return (\r or %0d) and line feed (\n or %0a) characters that separate HTTP headers. When these characters are injected into header values, attackers can insert arbitrary headers or terminate headers to inject body content.
Why is This Important?
CRLF injection is the foundation of HTTP response splitting attacks. It enables header manipulation, cookie injection, cache poisoning, and can be escalated to XSS by injecting malicious content into the response body.
How It Works
1. Web Crawling
Intelligent crawling discovers all endpoints, forms, parameters, and dynamic content across your web application.
2. Payload Injection
AI-powered payloads test each input vector for web vulnerabilities with context-aware attack patterns.
3. Response Analysis
Advanced analysis detects vulnerability signatures in responses, confirming exploitability with proof-of-concept.
Key Capabilities
Industry-leading web security testing powered by AI, trusted by security teams worldwide for accurate vulnerability detection.
- Deep web crawling with JavaScript rendering support
- Context-aware payload generation for each parameter
- False positive elimination through response analysis
- OWASP Top 10 and CWE compliance mapping
- Seamless CI/CD and DevSecOps integration
Frequently Asked Questions
What's the difference between CRLF and header injection?
CRLF injection is the technique (injecting line breaks). Header injection is the result (arbitrary headers added). CRLF injection enables header injection attacks.
Where does CRLF injection occur?
In any user input that ends up in HTTP headers: redirect URLs, cookie values, file names in Content-Disposition, and any custom headers derived from user input.
How is CRLF used for XSS?
By injecting two CRLFs, attackers terminate headers and start the body, then inject HTML/JavaScript that executes when the browser renders the response.
What encoding bypasses exist?
URL encoding (%0d%0a), Unicode variations, double encoding, and different CRLF representations depending on the server and framework.
Related Scanners
Ready to secure your application?
Start testing for crlf injection vulnerabilities today.
Get Started Free