FFUF, which stands for “Fast File Fuzzing,” is a powerful and flexible web fuzzer tool that helps security researchers and penetration testers uncover vulnerabilities in web applications. By automating the process of sending payloads and analyzing responses, FFUF streamlines the discovery of potential security weaknesses, enabling users to effectively enhance the security of their web applications.
How FFUF Works
This tool is designed to identify various types of vulnerabilities, such as directory traversal, server misconfigurations, and hidden files. It achieves this by fuzzing, which involves modifying parts of a URL or an HTTP request and observing how the application responds to different inputs.
The key features of FFUF include:
- Fast and Concurrent Fuzzing: This web fuzzer tool is known for its speed and concurrent fuzzing capabilities. It can send a high volume of requests concurrently, allowing for rapid testing and efficient vulnerability discovery.
- Customizable Payloads: This web fuzzer tool allows users to define custom payloads, which are sets of data or strings that are systematically modified and injected into the target application’s parameters. This flexibility enables extensive testing and the discovery of specific vulnerabilities.
- Dynamic Output and Filtering: This web fuzzer tool provides real-time output during the fuzzing process, allowing users to monitor and analyze responses as they come in. It also supports output filtering, which allows users to focus on specific patterns or responses of interest.
- Follow Redirects and Authentication Support: This tool can automatically follow redirects, ensuring that it continues fuzzing even when a redirection occurs. It also supports various authentication mechanisms, making it suitable for testing applications with authentication requirements.
- Download a prebuilt binary from releases page, unpack and run!
- If you are on macOS with homebrew, ffuf can be installed with:
brew install ffuf
- If you have recent go compiler installed:
go install github.com/ffuf/ffuf/[email protected](the same command works for updating)
Or you can install FFUF from source:
How to Use FFUF
This tool offers a variety of command-line options for customization. Users provide target URL, specify the location of custom payloads if necessary, and set any additional options, such as filtering criteria or authentication parameters. FFUF then runs the fuzzing process and generates output based on the responses received.
The output displays the request and response information, including the HTTP status codes, response headers, and response bodies. Users can apply filters to focus on specific patterns or response codes, facilitating efficient vulnerability identification.
Note: you can scan for hidden parameter or directory with ParamSpider and the output automatically save with FUZZ keyword on the end of some suspicious web directory. Then you can run FFUF to find juicy file on web application.
Typical directory discovery
By using the FUZZ keyword at the end of URL (
Virtual host discovery (without DNS records)
Assuming that the default virtualhost response size is 4242 bytes, we can filter out all the responses of that size (
-fs 4242)while fuzzing the Host – header:
POST data fuzzing
This is a very straightforward operation, again by using the
FUZZ keyword. This example is fuzzing only part of the POST request. We’re again filtering out the 401 responses.
Filter the output to match response code
More elaborate documentation that goes through many features with a lot of examples is available in the ffuf wiki, click here
FFUF is a highly effective and efficient web fuzzer tool that simplifies the process of identifying vulnerabilities in web applications. Its speed, concurrency, and customizable payload options make it a valuable asset for security researchers and penetration testers.
However, it’s important to note that this directory fuzzer tool should be used responsibly and with proper authorization. Fuzzing should only be performed on systems or applications for which you have permission to test. Additionally, it’s crucial to follow responsible disclosure practices by reporting any vulnerabilities discovered to the appropriate stakeholders so they can be addressed promptly.