Home 0P3N Blog Cracking Encrypted PDF Password Using Dictionary Attack
Ready to Start Your Career?
Create Free Account
Shaquib Izhars profile image
By: Shaquib Izhar
February 15, 2018

Cracking Encrypted PDF Password Using Dictionary Attack

By: Shaquib Izhar
February 15, 2018
Shaquib Izhars profile image
By: Shaquib Izhar
February 15, 2018

 In this post we will crack encrypted PDF with a very easy method. This is a very simple and easy method for cracking encrypted PDF password which is helpful for beginners in password cracking. There are also different method for cracking PDF password by generating hash and cracking it with John the Ripper but we are going to use dictionary attack for this. 
Lets crack the code
In below screen shot we can see when i am trying to access a PDF its asking for password.
 

 
 STEP 1 First open your terminal and type apt-get install pdfcrack -y and press return.
 

 
It will install pdfcrack on your machine 
 

 
 Now before cracking the password we need do generate some wordlist by keeping in mind our target, before doing this we have to do some reconnaissance to gather information about our victim. 
 
STEP 2  After gathering enough information about our target its time to generate wordlist . To do this first type apt-get install cupp and then type cupp -i.
 
STEP 3  cupp will ask for your target information like his name, his Surname, DOB, pet name so just enter your target information as asked.
 

 
STEP 4  It will ask to enter some keywords that could be victim's nick name , phone number etc. So enter your custom words as shown below.
 

 
STEP 5  Now it will ask for enter random number at end of word and to enable l33t mode , You can use this options if your target is some geek or computer enthusiasm so in this case i am going to use these options and then it will create your wordlist.
 

 
STEP 6  It is possible that the password may not be found in this wordlist and could be some random words so i am going to merge this with some large wordlist for this i am going to use rockyou.txt which you can find at /usr/share/wordlists/  extract this at the same place where your generated wordlist is.
 
STEP 7  Now its time to merge these two wordlist, for this type cat "your older wordlist name" "other wordlist name " >  "new wordlist name".
 
For example in this case it will be cat shaquib.txt rockyou.txt > modified.xt
 

 
STEP 8  We have prepared our hack now its time to crack the pdf so type pdfcrack -f "your pdf name" -w your created wordlist" as in this case pdfcrack -f /root/downloads/encrypted.pdf -w /root/Desktop/modified.txt  
 

 
It will start the Attack 
 

 
And within some minutes we successfully cracked the password of this encrypted PDF file.
 

For more stuff you can follow us on : Facebook
And you can also follow our Page  
 
 
 
 
Schedule Demo

Build your Cybersecurity or IT Career

Accelerate in your role, earn new certifications, and develop cutting-edge skills using the fastest growing catalog in the industry