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ffuf - Fuzz The Web

ffuf - Fuzz The Web


ffuf, is a web fuzzer written in Golang by @joohoi. Hackers use ffuf to fuzz directories, subdomains, virtual hosts, usernames, passwords, cookies, anything inside a HTTP request. The tool requires URL or HTTP request, and a wordlist to fuzz.


FUZZ is the secret. You need to put the word "FUZZ" wherever you want to fuzz, and provide a wordlist. You want to fuzz subdomains, input will be https://FUZZ.target.com with a wordlist of subdomains. You want to fuzz endpoints of a REST API, input will be https://target.com/api/v1/FUZZ with a wordlist of api endpoints.

Installation Ways:

  • Go Installation
$ go install github.com/ffuf/ffuf/v2@latest
  • Download binary from Releases
 Go to https://github.com/ffuf/ffuf/releases
  • MacOS brew Installation:
$ brew install ffuf
  • Compile and Build
$ git clone https://github.com/ffuf/ffuf
$ cd ffuf
$ go get
$ go build

Basic Usage:

Fuzzing directories

-w option for providing a wordlist and -u option to provide a URL. Here, I am fuzzing directories because the keyword FUZZ is present at directory location.

$ ffuf -w <wordlist.txt> -u https://<target.com>/FUZZ

Basic Filters/Matchers

To remove 301 status code results, use -fc option (filter code)

$ ffuf -w <wordlist.txt> -u https://<target.com>/FUZZ -fc 301
  • To only match results with 200 status code, use -mc option (match code)
$ ffuf -w <wordlist.txt> -u https://<target.com>/FUZZ -mc 200
  • Well, ffuf has lot of options. Lottttt!! I will cover most of them here.

Redirection and Control

Use -r for follow redirects (301, 302 redirection), -t for threads and -rate for requests/second control.

$ ffuf -r -t 100 -rate 1000 -w <wordlist.txt> -u https://<target.com>/FUZZ

Proxying ffuf traffic

  • Use -c to colorize the output, -x to proxy the traffix, -fs for filtering out results by there response size. -fs 0 will not match any results that have zero length.
$ ffuf -c -x http://<IP>:<PORT> -r -fs 0 -w <wordlist.txt> -u https://<target.com>/FUZZ
  • Proxying traffic is very helpful when we are fuzzing more critical locations inside a request. It helps to debug each request and response properly.

Fuzzing for Subdomains

  • You can also fuzz to find subdomains. Just use the FUZZ keyword before the domain part, FUZZ.target.com.

Fuzzing User-Agents

  • What about fuzzing a request's User-Agent? Yess, you can FUZZ user agents as well. You can fuzz any place where you will specify this keyword FUZZ.
  • Use -H option to specify HTTP headers. User-Agent is also a HTTP header.
$ ffuf -w <user-agents-wordlist.txt> -u https://google.com/robots.txt -H 'User-Agent: FUZZ'
  • Sometimes, servers are configured in such a way that response will only be given when particular User-Agent is present in the request. This trick helps to bypass 403/404 errors in some cases. The above one with google.com is just an example, robots.txt is already globally accessible.


  • We have seen -fs option to filter out responses on the basis of response size. ffuf also helps to filter out responses on the basis of lines (-fl), response time (-ft), words (-fw), status codes (-fc), and regex patterns (-fr).


  • There are matchers to match particular response codes (-mc), response size (-ms), lines (-ml), words (-mw), etc.

Methods and POST data

  • To use POST, PUT, DELETE as method. Use -X option and -d to provide body and here I have used -H to provide Content-Type HTTP header with application/json as value.
$ ffuf -X POST -H 'Content-Type: application/json' -d '{"username":"FUZZ"} -u https://<target.com>/api/username/exists -w <usernames-wordlist.txt>

Inputs inside Request

Cookies, HTTP headers, methods, request body, parameters everything can be provided with the options provided in ffuf.

$ ffuf -H <HTTP-headers> -b <Cookies> -X <method> -d <POST-body> -w <wordlist.txt> -u http(s)://<target.com>/
  • Attacker can use FUZZ keyword anywhere inside cookies, body, headers, URL, etc.

Intruder Attacks

  • How to do a sniper attack or clusterbomb attack like we do in Burpsuite Intruder with ffuf? Let me explain how.
$ ffuf -w <usernames.txt>:USER -w <passwords.txt>:PASS -X GET -u https://target.com/login?username=USER&password=PASS -mode <sniper/clusterbomb/pitchfork>

Raw HTTP Request

  • What about using a raw HTTP request as input? Use -request option. Inside the request write "FUZZ" wherever you would like to fuzz with the wordlist.
  • Suppose you have list of user-ids and particular request is vulnerable to IDOR. If the POST data body is too big. Just save the request in a text file. Write FUZZ at the location where you want to fuzz and a wordlist of userids and b00m!!
$ ffuf -request http-req.txt -w <wordlist.txt> -c 

Tips for beginners:

  • Use options like -mr to match regex patterns to match strings and regex patterns for sensitive leaks inside responses.
  • Filter the responses as much as you can by using options like -fw, -fs and -fl so that you are left with good results only.
  • Proxy the traffic using a proxy software like Zap or Burpsuite to visualize what's going on when it is running? How much traffic is flowing and at what rate?
  • Control the rate and threads as per the program policies to avoid getting banned from the program.

Inderjeet Singh
Want some help, message me on Twitter @3nc0d3dGuY
Happy Hacking!!