Hackfail.htb [patched] -

Falafel.htb is a masterfully designed difficulty machine that tests multiple skills: web application enumeration, SQL injection, hash manipulation, file upload exploitation, and creative privilege escalation through group abuse.

Because the maintenance routine checks relative locations, we can inject a custom payload into write-accessible system paths (such as /tmp or /dev/shm ) to hijack execution flow:

: Open, running OpenSSH. Useful for stable credentialed access later. hackfail.htb

After adding the IP address to /etc/hosts as falafel.htb , navigating to http://falafel.htb reveals a social network for falafel lovers with a login form. The source code provides no immediate clues, so automated directory fuzzing is required.

# Extract the admin's hash (retrieved via SQL injection) # The hash '0e462096931906507119562988736854' will match any other '0e' hash # Common candidates include 'QNKCDZO' or '240610708' Falafel

He crafted a new payload, wrapping a Jinja2 syntax probe inside a malformed error report.

Run a comprehensive scan to identify open ports and service versions. nmap -sC -sV -oA nmap_scan Use code with caution. Copied to clipboard After adding the IP address to /etc/hosts as falafel

The implementation relies on Python’s native eval() function to sanitize or format incoming client structures. Because user_input is directly embedded into the string template without validation, an attacker can break out of the string boundary and force the server to execute arbitrary system code (Remote Code Execution). Weaponizing the Payload

The first step in solving the Hackfail challenge is to perform initial reconnaissance. This involves scanning the target system to identify open ports and services.