I have a video showing how to use oclHashcat to crack PDF passwords, but I was also asked how to do this with John The Ripper on Windows.
It’s not difficult.
Download the latest jumbo edition john-the-ripper-v1.8.0-jumbo-1-win-32.7z from the custom builds page.
Decompress this version.
Download the previous jumbo edition John the Ripper 1.7.9-jumbo-5 (Windows binaries, ZIP, 3845 KB).
Extract file cyggcc_s-1.dll from the previous jumbo edition, and copy it to folder John-the-Ripper-v1.8.0-jumbo-1-Win-32run.
Generate the hash for the password protected PDF file (I’m using my ex020.pdf exercise file) and store it in a file (pdf2john.py is a Python program, so you need to have Python installed):
John-the-Ripper-v1.8.0-jumbo-1-Win-32runpdf2john.py ex020.pdf > ex020.hash
Start John The Ripper:
John-the-Ripper-v1.8.0-jumbo-1-Win-32runjohn.exe ex020.hashLoaded 1 password hash (PDF [MD5 SHA2 RC4/AES 32/32]) Will run 8 OpenMP threads Press 'q' or Ctrl-C to abort, almost any other key for status secret (ex020.pdf) 1g 0:00:00:00 DONE 2/3 (2015-03-29 22:39) 10.20g/s 125071p/s 125071c/s 125071C/s 123456..crawford Use the "--show" option to display all of the cracked passwords reliably Session completed
By starting John The Ripper without any options, it will first run in single crack mode and then in wordlist mode until it finds the password (secret).
But you can also provide your own wordlists (with option –wordlist) and use rules (option –rules) or work in incremental mode (–incremental).