Htb Skills Assessment - Web Fuzzing Exclusive -

The Hack The Box (HTB) Skills Assessment for Web Fuzzing is a practical capstone for the Attacking Web Applications with Ffuf module. It requires a systematic application of directory discovery, VHost identification, and parameter fuzzing to uncover hidden flags. 1. Understanding the Objective

The assessment tests your ability to use ffuf (Fuzz Faster U Fool) to map an application's hidden attack surface. Success relies on choosing the correct wordlists—typically from SecLists—and applying filters to remove "noise" like common 403 or 404 responses. 2. Core Methodology & Techniques Directory and File Discovery

Begin by identifying the base structure of the web server. Unlike standard reconnaissance, you must often use recursion to find nested directories like /admin/ and then fuzz within those for specific file types.

Command Example: ffuf -w common.txt -u http://:/FUZZ -recursion

Refinement: If you hit a 403 Forbidden on a directory, don't stop. Fuzz for extensions (e.g., .php, .php7, .html) within that directory to find accessible pages like panel.php. Virtual Host (VHost) Fuzzing

Servers often host multiple sites on one IP using Virtual Hosts. The assessment frequently requires discovering these by fuzzing the Host header.

Command: ffuf -w subdomains.txt -u http://:/ -H 'Host: FUZZ.academy.htb' -fs

Crucial Step: Once a VHost like admin.academy.htb is found, you must add it to your /etc/hosts file to interact with it through a browser or further tools. Parameter Fuzzing (GET and POST)

Once you find a hidden page, it may require specific parameters to function. You will use ffuf to discover both parameter names and their valid values.

GET Parameter Fuzzing: ffuf -w parameters.txt -u http://admin.academy.htb:/admin.php?FUZZ=key

POST Parameter Fuzzing: If GET fails, try POST by specifying the data flag: -X POST -d 'FUZZ=value'. 3. Key Assessment Tasks & Solutions HTB Academy Skills Assessment -Web Fuzzing | by Demacia

HTB Skills Assessment: Web Fuzzing – A Comprehensive Guide

In the realm of web security, "Fuzzing" is the art of the unknown. It’s the process of sending unexpected, malformed, or semi-random data to an application to see what breaks, what leaks, and what’s hidden. When you face the Hack The Box (HTB) Skills Assessment for Web Fuzzing, you aren't just looking for files; you are mapping the invisible attack surface of a target.

This guide breaks down the core methodology required to conquer the assessment and master the tools of the trade. 1. The Fuzzing Mindset: Beyond Directory Brute Forcing

Most beginners think fuzzing is just running dirb or gobuster to find /admin. In a professional assessment, fuzzing is used for: Directory/File Discovery: Finding hidden paths.

Vhost/Subdomain Discovery: Identifying virtual hosts that point to different environments (dev, stage, etc.).

Parameter Fuzzing: Finding hidden GET/POST parameters (e.g., ?debug=true).

Value Fuzzing: Identifying valid IDs, usernames, or bypasses. 2. Setting Up Your Toolkit

While many tools exist, ffuf (Fuzz Faster U Fool) is the industry standard for HTB assessments due to its speed and flexibility. Installation: sudo apt install ffuf -y Use code with caution.

Wordlists:You are only as good as your wordlist. Use SecLists.

Discovery: /usr/share/seclists/Discovery/Web-Content/directory-list-2.3-small.txt

Subdomains: /usr/share/seclists/Discovery/DNS/subdomains-top1million-5000.txt

Parameters: /usr/share/seclists/Discovery/Web-Content/burp-parameter-names.txt 3. Step-by-Step Assessment Strategy Phase A: Directory & File Discovery

Start by mapping the structure. HTB assessments often hide the "flag" or a sensitive login page behind non-standard extensions.

ffuf -w /path/to/wordlist.txt -u http://:/FUZZ -e .php,.html,.txt -ic Use code with caution.

-e: Specifies extensions (crucial for finding config.php.bak or info.php). -ic: Ignores wordlist comments. Phase B: Vhost Discovery

If the main IP returns a generic page, the real application might be hidden behind a Virtual Host. Since these aren't in public DNS, you must fuzz the Host header.

ffuf -w /path/to/wordlist.txt -u http://:/ -H "Host: FUZZ.target.htb" -fs 1495 Use code with caution. htb skills assessment - web fuzzing

-fs 1495: Filter Size. This is the most important flag. It hides responses that have a specific byte size (like the default "404" or "Welcome" page), allowing the unique vhosts to pop up. Phase C: Parameter Fuzzing (GET/POST)

Found a page but it’s blank? It might be waiting for a specific parameter. GET Fuzzing: ffuf -w /path/to/wordlist.txt -u http://target.htb -fs xxx Use code with caution.

POST Fuzzing:If GET yields nothing, the app might require data in the body.

ffuf -w /path/to/wordlist.txt -u http://target.htb -X POST -d "FUZZ=key" -H "Content-Type: application/x-www-form-urlencoded" Use code with caution. Phase D: Value Fuzzing

Once you find a parameter like id, you need to find the right value. ffuf -w ids.txt -u http://target.htb -fr "Invalid ID" Use code with caution.

-fr: Filter Regexp. Useful for hiding pages that contain the text "Invalid ID". 4. Pro-Tips for the HTB Assessment

Don't ignore the status codes: Sometimes a 403 Forbidden is more interesting than a 200 OK. Use -mc 200,301,302,403 to see them all.

Recursion: Use the -recursion flag to automatically fuzz directories inside directories that ffuf discovers.

Speed vs. Accuracy: HTB servers can sometimes hang if you fuzz too fast. Use -t 50 to adjust threads if you see timeouts.

Match the Output: Use -of md -o results.md to save your findings in Markdown for your final report. Conclusion

The HTB Web Fuzzing assessment isn't a test of how fast your computer is; it’s a test of how well you can filter out the noise. Master the -fs (Filter Size) and -fw (Filter Words) flags, and the "hidden" flags will reveal themselves.

This skills assessment on Hack The Box (HTB) typically tests your ability to use fuzzing tools to discover hidden content, subdomains, and parameters on a target web application.

Since you're looking for a "text" (likely a walkthrough or a summary of the methodology), here is a structured guide on how to approach the assessment using tools like ffuf, wfuzz, or gobuster. 1. Directory & File Fuzzing

Your first goal is to map out the web server’s structure. You want to find hidden directories or files that aren't linked on the main page.

The Goal: Find administrative panels, backups (like .bak, .old), or configuration files.

Key Command (ffuf):ffuf -w /usr/share/wordlists/dirb/common.txt -u http://:/FUZZ

Pro Tip: Always fuzz for extensions (e.g., -e .php,.html,.txt) to find functional scripts. 2. Subdomain & VHost Discovery

Sometimes the "flag" or the vulnerability is hidden on a different virtual host (like ://target.com or ://target.com).

VHost Fuzzing: Since you often don't have DNS control in HTB labs, you fuzz the Host Header.

Key Command:ffuf -w /usr/share/wordlists/seclists/Discovery/DNS/subdomains-top1million-5000.txt -u http://target.htb -H "Host: FUZZ.target.htb"

Filtering: Use -fs [size] to filter out "Default" page sizes that clutter your results. 3. Parameter Fuzzing (GET/POST)

Once you find a page (like config.php), it might be expecting a parameter you don't know about (e.g., ?file= or ?id=).

The Goal: Identify parameters that could lead to Local File Inclusion (LFI) or IDOR.

Key Command:ffuf -w /usr/share/wordlists/seclists/Discovery/Web-Content/burp-parameter-names.txt -u http:///page.php?FUZZ=test -fs [size] 4. Recursive Fuzzing

If you find a directory called /api, you should immediately fuzz inside that directory.

ffuf flag: Use -recursion and -recursion-depth 2 to automate this. Summary Checklist for the Assessment:

Identify the Target: Add the IP to your /etc/hosts file if a domain name is provided. The Hack The Box (HTB) Skills Assessment for

Basic Scan: Run a quick directory fuzz to find the "entry point."

VHost Check: Always check for subdomains if the main page looks like a dead end.

Parameter Hunting: If you find a page that does nothing, fuzz for hidden parameters.

Are you stuck on a specific question or flag within the assessment, or did you need a deeper explanation of the ffuf filters?

The Hack The Box (HTB) Web Fuzzing Skills Assessment requires using

to uncover hidden subdomains, directory structures, and parameters to retrieve a final flag. Key steps include VHost discovery, recursive directory enumeration, and fuzzing for specific parameter values to bypass security filters. For a detailed walkthrough of the assessment, visit Demacia's blog Web Fuzzing Course - HTB Academy

I’d be happy to help you with a Hack The Box (HTB) skills assessment focused on web fuzzing. However, I don’t have access to the specific live assessment or its unique flags/targets.

If you describe the type of web fuzzing involved (directory, parameter, virtual host, file extension, etc.) and share what you’ve tried so far (e.g., tools like ffuf, gobuster, wfuzz, dirb), I can:

  • Explain the correct fuzzing methodology for that scenario
  • Help interpret the response codes, sizes, or words that indicate a hit
  • Suggest filters to reduce noise (-fc, -fs, -fw, -fr)
  • Troubleshoot rate limiting, false positives, or authentication issues

Example helpful info I can provide (not task-specific, but generally useful for HTB web fuzzing):

  • Directory fuzzing:
    ffuf -u http://target.com/FUZZ -w wordlist.txt -fc 404 -fs 0

  • Extension fuzzing:
    ffuf -u http://target.com/indexFUZZ -w .txt,.php,.bak,.old -e

  • VHost fuzzing:
    ffuf -u http://target.com/ -H "Host: FUZZ.target.com" -w subdomains.txt -fs <size>

  • Parameter fuzzing (GET):
    ffuf -u http://target.com/page.php?FUZZ=test -w params.txt -fc 404

  • Parameter fuzzing (POST):
    ffuf -u http://target.com/login -X POST -d "FUZZ=test" -w params.txt -fc 400

If you share a snippet of the assessment’s prompt (without revealing live flags/violating HTB rules), I can guide you without giving direct answers.

Let me know where you’re stuck — response code filtering, wordlist choice, or interpreting a false positive?

This report summarizes the methodology and findings for the Hack The Box (HTB) Academy - Web Fuzzing Skills Assessment. The assessment focuses on using ffuf (Fuzz Faster U Fool) to systematically discover hidden resources, virtual hosts, and parameters to uncover security vulnerabilities. 1. Executive Summary

The objective of this assessment was to perform a comprehensive security analysis of a target web application using automated fuzzing techniques. By moving through progressive layers of discovery—from subdomains to specific parameter values—multiple hidden endpoints were identified, eventually leading to the final flag. 2. Methodology & Tooling

The primary tool used was ffuf, supported by wordlists from the SecLists collection, specifically directory-list-2.3-small.txt, common.txt, and subdomains-top1million-5000.txt. Key ffuf Flags Reconnaissance VHost & Subdomain Fuzzing -H 'Host: FUZZ.domain.htb', -ms 0 Enumeration Directory & File Fuzzing -u http://target/FUZZ, -e .php,.txt Expansion Recursive Fuzzing -recursion, -recursion-depth 1 Exploitation Parameter & Value Fuzzing -X POST, -d 'param=FUZZ', -fs 3. Assessment Workflow & Findings Step 1: Virtual Host (VHost) Discovery

Initial testing on the base IP often returns restricted access (e.g., 403 Forbidden). VHost fuzzing was conducted to identify hidden sub-sites.

Command: ffuf -w subdomains-wordlist.txt -u http://TARGET_IP/ -H 'Host: FUZZ.academy.htb' -ms 0

Findings: Identified subdomains such as archive.academy.htb, faculty.academy.htb, and test.academy.htb. Step 2: Extension & Directory Enumeration

Before searching for pages, an extension scan determined which file types the server processes.

Key Discovery: Extensions like .php and .phps were found to be active.

Recursive Fuzzing: Using -recursion uncovered a multi-level directory structure, including /courses/linux-security.php7. Step 3: Parameter Fuzzing

On the identified admin or panel pages, fuzzing was used to find hidden GET/POST parameters. Command: ffuf -w wordlist.txt -u http://academy.htb -fs 798

Findings: Discovered the accepted parameter id and accessID. Step 4: Value Fuzzing & Flag Retrieval Explain the correct fuzzing methodology for that scenario

The final step involved brute-forcing the specific values for identified parameters (e.g., finding the correct id number).

Action: Sent a POST request with the discovered value to retrieve the flag. Flag Format: HTB.... 4. Remediation Recommendations

To mitigate the risks identified during this assessment, the following security controls should be implemented:

Mastering the HTB Academy Web Fuzzing Skills Assessment requires a systematic approach to uncovering hidden layers of a web application using tools like

. This assessment tests your ability to move beyond basic directory brute-forcing and into advanced techniques like virtual host (VHost) discovery and parameter fuzzing. Essential Fuzzing Methodology

A successful assessment follows a logical progression of discovery:

HTB Skills Assessment - Web Fuzzing

Introduction

Web fuzzing is a crucial technique in web application security testing that involves sending a large number of inputs to a web application to discover hidden or unlinked resources, identify potential vulnerabilities, and understand the application's behavior under various conditions. As part of the Hack The Box (HTB) skills assessment, this challenge focuses on testing your proficiency in web fuzzing.

Objective

Your objective is to fuzz a given web application to discover as much information as possible, including but not limited to:

  1. Directories and Files: Identify any directories or files that are not directly linked but are accessible through fuzzing.
  2. Parameters and Possible Vulnerabilities: Discover hidden parameters, possible SQL injection points, cross-site scripting (XSS), and other vulnerabilities.
  3. API Endpoints: If the application has API endpoints, identify them and understand their functionality.

Tools and Techniques

For this assessment, you are encouraged to use a variety of tools such as:

  • Burp Suite (Intruder, Repeater, and Sequencer): For sending and analyzing large numbers of requests.
  • DirBuster or DirTraversal: For directory and file fuzzing.
  • Wfuzz: A web application fuzzer that can be used to identify vulnerabilities and enumerate web application components.
  • ZAP (Zed Attack Proxy): An open-source web application security scanner for identifying vulnerabilities.

Methodology

  1. Initial Scan: Begin with a basic scan using tools like Nmap or a simple web reconnaissance to understand the application's technology stack and open ports.
  2. Directory and File Fuzzing: Use tools like DirBuster or wfuzz to enumerate directories and files.
  3. Parameter Fuzzing: Look for parameters within the discovered files and directories. Tools like Burp Suite's Intruder can help here.
  4. Vulnerability Identification: For each discovered component, test for common vulnerabilities such as SQL injection, XSS, command injection, etc.
  5. Reporting: Document all findings, including any successful fuzzing results, potential vulnerabilities, and the tools/commands used.

Deliverables

Your submission should include:

  1. A detailed report on your fuzzing process and findings. This should include:
    • A list of all directories, files, and parameters discovered.
    • Potential vulnerabilities identified, along with examples of payloads used to exploit them.
    • Screenshots or logs of your findings for verification.
  2. A summary of your approach to the challenge and any insights gained.

Grading Criteria

  • Effectiveness: The extent to which you were able to discover new information (directories, files, parameters) and potential vulnerabilities.
  • Methodology and Approach: A clear and thorough approach to web fuzzing, including the tools chosen and why.
  • Documentation: Clarity, completeness, and organization of your report.

Submission Guidelines

Please submit your report as a PDF document to [insert submission email/dropbox link]. Ensure your subject line reads: "HTB Skills Assessment - Web Fuzzing [Your Username]".

Additional Notes

  • Ensure you have permission from Hack The Box to perform your assessment on their systems.
  • Respect data privacy and only report vulnerabilities through official channels.

This challenge is designed to assess your hands-on skills in web application security testing, specifically in web fuzzing. Good luck!

Phase 3: Parameter & VHost Fuzzing (The Gatekeeper)

This is where beginners fail the HTB assessment. You found a page like http://target.htb/api.php. It returns a blank page. Now what?

Parameter Fuzzing: You need to guess the HTTP parameter the script expects.

ffuf -u http://target.htb/api.php?FUZZ=test -w /usr/share/seclists/Discovery/Web-Content/burp-parameter-names.txt -fs 0

Flag -fs 0 filters out responses with a content size of 0 bytes (blank pages).

If you find a parameter like debug or file, you can then fuzz its value. For example, ?file=FUZZ to look for Local File Inclusion (LFI).

Virtual Host Fuzzing: The assessment may hide a second application on a different Virtual Host.

ffuf -u http://10.10.10.x/ -H "Host: FUZZ.target.htb" -w subdomains.txt -fs 5000

If you get a different response for admin.target.htb, add it to your /etc/hosts file and browse to it. This new vhost is often the actual target of the assessment.

Filtering Out Noise

  • -fc 404 (Filter out 404 Not Found)
  • -fs 0 (Filter out empty responses)
  • -fw 42 (Filter out responses with 42 words—great for custom 404 pages)
  • -fl 100 (Filter out lines)

5.2 Extension Fuzzing

If you find admin.php, fuzz for admin.bak, admin.txt, admin.sql:

ffuf -u http://target.com/adminFUZZ -w extensions.txt

Key Takeaways for the Exam:

  1. Start wide, then go deep: Fuzz root -> fuzz subdirs -> fuzz parameters.
  2. Read every response: A Content-Length difference of 4 bytes can indicate a found parameter.
  3. Use multiple wordlists: If directory-list-2.3-medium fails, the answer is in raft-large-directories.
  4. Don't forget robots.txt and sitemap.xml: Sometimes the assessment hand-feeds you the first fuzzing target.

5.5 Virtual Host Fuzzing (with Host header)

ffuf -u http://10.10.10.10 -H "Host: FUZZ.target.com" -w subdomains.txt -fs 1234
  • Identifies hidden vhosts that may host different applications.