Hack The Box: Guardian Machine Walkthrough – Hard Difficulty
🔐 User Flag — Compromising the Application Layer
Successfully rooted the Guardian (Hard) machine on Hack The Box by chaining multiple real-world web vulnerabilities.Initial access was achieved through credential abuse and IDOR within the student portal. Leaked chat credentials exposed internal Gitea repositories containing hardcoded database secrets. A vulnerable XLSX file upload feature allowed formula injection → XSS → session hijacking. Leveraging CSRF, I created a rogue admin account and escalated privileges within the application. From there, an LFI vulnerability combined with a PHP filter chain led to Remote Code Execution. After gaining a shell as www-data, I reused leaked credentials to pivot laterally to user jamil, capturing the user flag.
👑 Root Flag — From Code Injection to Full System Compromise
Privilege escalation started with sudo -l, revealing that jamil could execute a Python utility as user mark without a password. Since one of the Python files was writable, I injected code to spawn a shell as mark. Further enumeration uncovered a custom binary (safeapache2ctl) executable as root. A flawed validation mechanism in its Apache config parsing allowed path traversal and arbitrary file inclusion. By crafting a malicious shared object (evil.so) and abusing the wrapper’s improper include validation, I achieved root-level code execution and obtained a root shell.
