Pdfy Htb Writeup Upd [verified] πŸ“Œ

: Use the --disable-local-file-access flag for wkhtmltopdf .

Upon launching the challenge, you are greeted with a simple web interface that prompts for a URL. The application’s stated purpose is to "turn your favorite web pages into portable PDF documents".

We can create a malicious configuration file to escalate privileges. Our plan is to create a symbolic link to the /etc/passwd file and modify it to add a new root user.

is a challenge focused on Server-Side Request Forgery (SSRF) and Local File Inclusion (LFI) via a PDF generation tool. HacktheBox Writeup: Paper - InfoSec Write-ups pdfy htb writeup upd

Review how to perform when a PDF preview is not explicitly shown. Share public link

To bypass this restriction, you must use a . By hosting an external script that sends a redirect header to a local resource, the backend parser follows the redirect internally, circumventing the frontend URL filtering. 2. Step-by-Step Walkthrough Step 1: Initial Reconnaissance

Force the binary flags (such as --disable-local-file-access in modern implementations) to isolate the application completely from system-level protocols like file:// . : Use the --disable-local-file-access flag for wkhtmltopdf

Hack The Box: PDFy Challenge Walkthrough (UPDATED) The Hack The Box (HTB) challenge is an excellent, real-world emulation of a Server-Side Request Forgery (SSRF) vulnerability that leverages a backend PDF rendering engine. The core objective of this challenge is to trick the application's HTML-to-PDF converter into reading local system files and exposing the root flag.

: We navigate to the user's home directory (e.g., /home/username ) and read the user.txt file.

The tool wkhtmltopdf is a widely known open-source command-line tool used to render HTML into PDF using the WebKit rendering engine. Historically, older versions of this library are highly susceptible to and SSRF through embedded HTML objects, frames, or scripts. We can create a malicious configuration file to

To secure similar applications, developers are encouraged to use allow-lists for input, implement secure coding frameworks, and perform regular vulnerability scans to identify outdated or misconfigured libraries.

ngrok will provide a public address, for example, tcp://0.tcp.us-cal-1.ngrok.io:19086 . However, the PDFy application expects an http:// URL. We can simply replace tcp:// with http:// in our payload. So our final attacker server address becomes http://0.tcp.us-cal-1.ngrok.io:19086 .