Hackfail.htb ((exclusive)) -

Complete Walkthrough: Mastering Hackfail.htb Hackfail.htb is a medium-difficulty Linux machine on Hack The Box that tests your web application analysis, source code review, and advanced privilege escalation skills. This article provides a comprehensive, step-by-step guide to exploiting this machine, from initial enumeration to gaining root access. 1. Initial Reconnaissance and Port Scanning

The environment feels restricted, indicating that the initial foothold is contained within a Docker container or a highly sandboxed environment. Look for configuration files related to the web application or Fail2ban setup. Inspecting Fail2ban Configurations

Add the target domain to your local hosts file before proceeding: echo "10.10.11.XXX hackfail.htb" | sudo tee -a /etc/hosts Use code with caution. Phase 2: Web Reconnaissance and Log Injection

Access Denied. You are trying too hard.

Update your local management file ( /etc/hosts ) to resolve these domains cleanly: 10.129.x.x hackfail.htb dev.hackfail.htb api.hackfail.htb Use code with caution. 2. Foothold: From Code Audit to Remote Code Execution

Look for standard ports like 80 (HTTP) , 443 (HTTPS) , or 22 (SSH) . 2. Web Enumeration If port 80/443 is open, explore the web application:

He copied the flag, pasted it into the submission box, and watched the points tick up. hackfail.htb

The information contained in this article is for educational purposes only. Hack The Box and hackfail.htb are legitimate platforms that provide a safe and controlled environment for testing penetration testing skills. Any attempts to exploit vulnerabilities or engage in malicious activities outside of the authorized Hack The Box environment are strictly prohibited and potentially punishable by law. Always ensure you have the necessary permissions and follow applicable laws and regulations when engaging in cybersecurity activities.

Once inside the initial environment, run basic enumeration scripts like LinPEAS or check internal configurations manually. whoami id Use code with caution.

: Use the OpenVPN file provided by HTB to access their private lab network. Edit your Hosts File : Map the domain to the target IP address (e.g., 10.10.x.x hackfail.htb /etc/hosts file so your browser can resolve the name. : Use tools like for scanning and for finding hidden directories or subdomains. Complete Walkthrough: Mastering Hackfail

The terminal didn't return a 403 . It didn't return a 404 . It hung for a heartbeat, and then vomited a 500 Internal Server Error . But buried inside the HTML response body, hidden in a developer comment tag, was the prize.

The vulnerability lies in how Fail2ban processes the "user" or "host" token in the log. If the Fail2ban action configuration uses an unsafe command execution wrapper—such as passing the extracted username directly into a shell command without sanitization—you can achieve Remote Code Execution (RCE). Weaponizing the Payload

Craft an SSH login attempt where the username contains a reverse shell payload enclosed in backticks or command substitution syntax: Phase 2: Web Reconnaissance and Log Injection Access

Use a payload (like a PHP reverse shell) to connect back to your listener ( nc -lvnp ).