PDF bruteforce tool to recover locked files

• Author: Solène
• Date: 09 March 2025
• Tags: security

Introduction

Today, I had to open a password protected PDF (medical report), unfortunately it is a few years old document and I did not remember the password format (usually something based on named and birthdate -_-).

I found a nice tool that can try a lot of combinations, and it is even better as if you know a bit the password format you can easily generate tested patterns.

Usage

The project page offers binaries for some operating systems, but you can compile it using cargo.

The documentation on the project's README is quite clear and easy to understand. It is possible to generate some simple patterns, try all combinations of random characters or use a dictionary (some tools exists to generate a dictionary).

Inside a virtual machine with 4 vCPU, I was able to achieve 36 000 checks per second, on baremetal I expect this to be a higher.