API Fuzzing for Bug Bounty

What it does

This skill enables AI agents to automatically generate and execute diverse payloads against API endpoints to identify vulnerabilities. It systematically tests inputs for injection flaws, logic errors, and unexpected behaviors that could lead to security breaches.

When to use it

• Pre-engagement scanning: Run automated fuzzing campaigns on public APIs before manual penetration testing to map potential attack surfaces.
• Regression validation: Verify that recent code deployments haven't introduced new injection vectors or broken input sanitization.
• Parameter stress testing: Evaluate how an API handles malformed data, oversized requests, or unusual character sets in query strings and bodies.
• Logic flaw discovery: Attempt to bypass authentication checks or trigger unintended state changes by sending unexpected parameter combinations.

Key capabilities

• Automated payload generation for common vulnerability classes (SQLi, XSS, command injection).
• Endpoint enumeration to discover hidden or undocumented API routes.
• Payload mutation strategies to refine test cases based on server responses.
• Structured reporting of discovered issues with context and reproduction steps.

Example prompts

• "Use the fuzzing skill to scan the /api/v1/users endpoint for SQL injection vulnerabilities using standard payloads."
• "Generate a list of 50 unique payloads to test the file upload parameter at /upload for path traversal flaws."
• "Fuzz the authentication header in this API request to see if you can bypass token validation or extract sensitive data."

Tips & gotchas

Ensure you have explicit authorization to test the target APIs, as unauthorized fuzzing may violate terms of service or laws. Configure rate limiting and payload size constraints to avoid triggering defensive mechanisms like WAFs or causing denial-of-service conditions on the target system.