Tag: pdf

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How to convert Microsoft Office *.docx files to PDF using Linux in command-line

Here’s how to convert Microsoft Office *.docx files to PDF using Linux in Command Line.
This trick can also be used together with other documents files supported by LibreOffice

First make sure you’ve installed the latest version of LibreOffice for use in command line environment.
Assuming the user is ‘example’ and the filename to convert is ‘doc.pdf’.

libreoffice --headless -convert-to pdf --outdir /home/example/ /home/example/doc.docx

The conversion can also be adapted to PHP or Python using their respective shell_exec or subprocess directive.

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Download Wordlist for dictionary attack

Crackstation wordlist is one of the most (if not the most) comprehensive wordlist which can be used for the purpose of dictionary -attack on passwords.

The wordlist comes in two flavors:

  1. Full wordlist (GZIP-compressed (level 9). 4.2 GiB compressed. 15 GiB uncompressed)
  2. Human-password only wordlist (GZIP-compressed. 247 MiB compressed. 684 MiB uncompressed)

Personally, I’ve already downloaded the full wordlist via torrent, and tested it against few PDF files (using pdfcrack) and UNIX password cracking (using John), all my test cases were successful. In my opinion, the wordlist is comprehensive for my need.

Since it looked like it took a significant effort to compile this wordlist, I rather advocate those who are interested to donate/buy the wordlist from: https://crackstation.net/buy-crackstation-wordlist-password-cracking-dictionary.htm

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Cracking PDF file with PDFCrack in Linux

I’ve come across an PDF which was sent to my email from an automated banking system. Unfortunately, the PDF file is encrypted and I’ve no way of knowing the password (or actually I’ve forgotten the password).

Fortunately, my Ubuntu box comes with application which allows me to crack the PDF file within a reasonable time.

Using ‘pdfcrack’ to crack PDF file

You need to install pdfcrack to crack pdf file. In Ubuntu/Debian system, you simply need to run

sudo apt-get -y install pdfcrack

Then for actual cracking, you can run

pdfcrack -n5 -m10 encrypted.pdf

Where -n [minimum length] to brute-force, and -m [maximum length] to brute-force.

pdfcrack can also accept a file input containing list of words (dictionary attack). For dictionary-attack just run

pdfcrack --wordlist=dictionary.txt encrypted.pdf
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Book Giveaway: Linux Module Programming Guide

Free !

Listen up!

UbuntuGeek is giving away the “Linux Kernel Module Programming Guide” e-book for free! The book contains guides and tutorial on how to write loadable Linux kernel module and drivers.

According to its official description:

“An excellent guide for anyone wishing to get started on kernel module programming. The author takes a hands-on approach starting with writing a small “hello, world” program, and quickly moves from there. Far from a boring text on programming, Linux Kernel Module Programming Guide has a lively style that entertains while it educates”

Linux Kernel Module Programming Guide

Download now: Linux Kernel Module Programming Guide (PDF)

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Ubuntu Linux : How to combine multiple PDF file

Here’s how to combine multiple PDF file on Ubuntu.

First install ghostscript and pdftk from Ubuntu repository :

apt-get install gs pdftk

Then, using ghostscript, combile all the pdf files you desired into one file, using this command

[code]
s -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=combined_file.pdf -dBATCH file1.pdf file2.pdf file3.pdf
[/code]

The command will produced the combined pdf output on “combine_file.pdf”