How to crack / recover an Adobe PDF password using pdfcrack for Linux.
By Mike on Apr 9, 2008 in Hacks/Mods, How to, Linux, Software
From time to time I am asked to break a password on an Adobe PDF file. This mostly comes up when the user who created the pdf can’t remember what their own password is. As annoying as that is, actually recovering the password is simple using pdfcrack.
PDFCrack is a GNU/Linux application (or any other POSIX-compatible system) tool for recovering passwords and content from PDF-files. It is small, command line driven, and without external dependencies. PDFCrack is released under GPL.
Install pdfcrack on Ubuntu by typing:
sudo aptitude install pdfcrack
Run a quick benchmark by entering the following at the command line:
pdfcrack -b
Results:
Benchmark: Average Speed (calls / second):
MD5: 2616026.7
MD5_50 (fast): 146928.3
MD5_50 (slow): 107780.3
RC4 (40, static): 863985.7
RC4 (40, no check): 864661.2
RC4 (128, no check): 802203.0
Benchmark: Average Speed (passwords / second):
PDF (40, user): 653588.2
PDF (40, owner): 322317.1
PDF (40, owner, fast): 714278.6
PDF (128, user): 30861.1
PDF (128, owner): 14687.8
PDF (128, owner, fast): 30861.1
Use pdfcrack to crack an encrypted pdf-file by typing:
pdfcrack test.pdf
Popularity: 15% [?]
Sarah | Apr 11, 2008 | Reply
Good little utility, figured I’d post here as TBQFH every where else on the net has ‘pay us for versions that don’t take a week+’ and this little bugger churns though.
admin | Apr 11, 2008 | Reply
Yep. takes about five mins. on average for me. Depends on the computer.