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Guide to Using FFUF for Web Fuzzing

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FFUF (Fuzz Faster U Fool) is a fast web fuzzer written in Go language, used for quickly and efficiently discovering hidden files and directories on web servers. Below is a guide on how to use FFUF for web fuzzing:

1. Install FFUF:

  • Download: You can download the FFUF binary from the GitHub releases page or install it using a package manager like apt or yum on Linux systems.

2. Basic Usage:

  • Fuzzing URLs:
  ffuf -u <target_URL> -w <wordlist>

Replace <target_URL> with the target URL to fuzz and <wordlist> with the path to the wordlist file containing directory and file names to fuzz.

3. Advanced Options:

  • Custom Headers:
  ffuf -u <target_URL> -w <wordlist> -H "Header: Value"

Use the -H option to specify custom headers in the HTTP request.

  • Recursion:
  ffuf -u <target_URL> -w <wordlist> -recursion -recursion-depth 2

Use the -recursion option to enable directory recursion and specify the recursion depth using -recursion-depth.

  • Filtering Responses:
  ffuf -u <target_URL> -w <wordlist> -fc 404,403

Use the -fc option to filter out responses with specific status codes.

  • Multithreading:
  ffuf -u <target_URL> -w <wordlist> -t 50

Use the -t option to specify the number of concurrent threads.

  • Output Format:
  ffuf -u <target_URL> -w <wordlist> -o <output_file>

Use the -o option to specify the output file format (e.g., json, html, csv).

4. Filter Options:

  • Filter by Size:
  ffuf -u <target_URL> -w <wordlist> -fs 1000 -fl 2000

Use the -fs option to filter out responses smaller than a specified size and -fl to filter out responses larger than a specified size.

  • Filter by Regex:
  ffuf -u <target_URL> -w <wordlist> -fr "regex_pattern"

Use the -fr option to filter responses using a regex pattern.

Tips and Considerations:

  • Wordlists: Use custom wordlists tailored to your target and the context of your assessment for better results.
  • Thoroughness vs. Speed: Adjust the number of threads and other options based on the desired balance between thoroughness and speed.
  • Be Mindful of Server Load: Fuzzing with too many threads or aggressively may overload the target server, leading to unintended consequences.
  • Authorization: Ensure that you have proper authorization before fuzzing any web application or server.
  • Error Handling: Handle errors gracefully and monitor the tool’s output for any unexpected behavior.

By following this guide, you can effectively use FFUF for web fuzzing to discover hidden files and directories on web servers. Always use such tools responsibly and ethically, and ensure compliance with applicable laws and regulations.