Introduction
Hidden parameters in web applications can often lead to exciting discoveries for security testers. These parameters, though invisible to regular users, may expose sensitive functionalities or vulnerabilities. In this guide, we’ll explore how to find hidden parameters and discuss the essential tools and techniques required for the job.
Step 1: Understanding Hidden Parameters
Hidden parameters are additional inputs in web applications that aren't directly visible in URLs or forms. They can include debugging options, admin functions, or other developer-intended shortcuts.
Why Hidden Parameters Matter
- They can expose sensitive data.
- They may allow unauthorized access to features.
- Debugging functionalities can reveal internal application logic.
Step 2: Analyzing the Web Application
Start by examining the web application to identify potential entry points for hidden parameters.
Key Areas to Focus On
- Forms and Input Fields:
Check for forms where additional parameters could be added. - URLs:
Inspect query strings for patterns and structures. - HTTP Requests:
Review all HTTP requests made during normal application usage.
Step 3: Tools for Discovering Hidden Parameters
Using the right tools is essential for efficiently uncovering hidden parameters. Here are five essential tools:
1. Burp Suite
- Intercept HTTP/HTTPS traffic and manipulate requests to test additional parameters.
- Use Intruder and Repeater to automate parameter fuzzing.
2. ParamSpider
- Automatically extract URLs with parameters from the target website.
- Crawl the application to discover hidden endpoints.
3. Arjun
- Specialized tool for finding hidden GET and POST parameters.
- Fuzz large parameter dictionaries against endpoints.
4. Ffuf
- Fast and flexible fuzzer for URLs, headers, and parameters.
- Ideal for testing multiple combinations quickly.
5. Google Dorks
- Use advanced search queries to discover application-specific documentation or endpoints.
Step 4: Techniques for Parameter Discovery
A. Manual Testing
- Add common parameters manually to URLs (e.g.,
?debug=true,?admin=1). - Test responses for any unusual or additional functionality.
B. Parameter Fuzzing
- Use tools like Burp Suite and Ffuf to inject parameter lists into the application.
- Analyze server responses for changes or errors indicating parameter acceptance.
C. Crawling the Application
- Use tools like ParamSpider to identify endpoints with potential parameters.
- Review the site's robots.txt and sitemap.xml for hidden paths.
Step 5: Validating Findings
After identifying hidden parameters, ensure they’re legitimate and test their functionality safely.
Steps to Validate
- Confirm their presence by sending controlled inputs.
- Check if they expose sensitive information or functionality.
- Report responsibly if vulnerabilities are discovered.
Conclusion
Discovering hidden parameters is a crucial skill for bug hunters and security testers. By leveraging the techniques and tools mentioned in this guide, you can uncover valuable insights into web applications and potentially discover critical vulnerabilities.
Happy hunting!