What is Password Cracking?

• Crack Pdf Security Password Free
• Crack Pdf Security Password Change
• Remove Pdf Password Security
• Crack Pdf Security Password

PDF security cracker for Mac is an incredible utility to crack Adobe PDF security password. There are multiple reliable features offered by the tool that makes the process to crack PDF security much easier. The application comprises a self-explanatory and user-friendly GUI so, a non-technical user can operate it without any expert help. Some companies such as Elcomsoft specialize in PDF password remover tools using various methods such as dictionary attacks and brute force to eventually crack the password. Be wary of PDF password remover tools that offer an online service because you have to upload your PDF file to their servers and it is decrypted there. Before starting to remove PDF security without password, we should know there are two kinds of PDF password: a. User password (or called open password). People always set this kind of password to protect their PDF files from being opened by others, unless the PDF file's owner tell you the correct user password, you can't open or view the user-password-protect PDF files; b.

Password cracking is the process of attempting to gain Unauthorized access to restricted systems using common passwords or algorithms that guess passwords. In other words, it’s an art of obtaining the correct password that gives access to a system protected by an authentication method.

Password cracking employs a number of techniques to achieve its goals. The cracking process can involve either comparing stored passwords against word list or use algorithms to generate passwords that match

In this Tutorial, we will introduce you to the common password cracking techniques and the countermeasures you can implement to protect systems against such attacks.

Topics covered in this tutorial

What is password strength?

Password strength is the measure of a password’s efficiency to resist password cracking attacks. The strength of a password is determined by;

• Length: the number of characters the password contains.
• Complexity: does it use a combination of letters, numbers, and symbol?
• Unpredictability: is it something that can be guessed easily by an attacker?

Let’s now look at a practical example. We will use three passwords namely

1. password

2. password1

3. #password1$

For this example, we will use the password strength indicator of Cpanel when creating passwords. The images below show the password strengths of each of the above-listed passwords.

Note: the password used is password the strength is 1, and it’s very weak.

Note: the password used is password1 the strength is 28, and it’s still weak.

Note: The password used is #password1$ the strength is 60 and it’s strong.

The higher the strength number, better the password.

Let’s suppose that we have to store our above passwords using md5 encryption. We will use an online md5 hash generator to convert our passwords into md5 hashes.

The table below shows the password hashes

Password	MD5 Hash	Cpanel Strength Indicator
password	5f4dcc3b5aa765d61d8327deb882cf99	1
password1	7c6a180b36896a0a8c02787eeafb0e4c	28
#password1$	29e08fb7103c327d68327f23d8d9256c	60

We will now use http://www.md5this.com/ to crack the above hashes. The images below show the password cracking results for the above passwords.

As you can see from the above results, we managed to crack the first and second passwords that had lower strength numbers. We didn’t manage to crack the third password which was longer, complex and unpredictable. It had a higher strength number.

Password cracking techniques

There are a number of techniques that can be used to crack passwords. We will describe the most commonly used ones below;

• Dictionary attack– This method involves the use of a wordlist to compare against user passwords.
• Brute force attack– This method is similar to the dictionary attack. Brute force attacks use algorithms that combine alpha-numeric characters and symbols to come up with passwords for the attack. For example, a password of the value “password” can also be tried as p@$$word using the brute force attack.
• Rainbow table attack– This method uses pre-computed hashes. Let’s assume that we have a database which stores passwords as md5 hashes. We can create another database that has md5 hashes of commonly used passwords. We can then compare the password hash we have against the stored hashes in the database. If a match is found, then we have the password.
• Guess– As the name suggests, this method involves guessing. Passwords such as qwerty, password, admin, etc. are commonly used or set as default passwords. If they have not been changed or if the user is careless when selecting passwords, then they can be easily compromised.
• Spidering– Most organizations use passwords that contain company information. This information can be found on company websites, social media such as facebook, twitter, etc. Spidering gathers information from these sources to come up with word lists. The word list is then used to perform dictionary and brute force attacks.

Spidering sample dictionary attack wordlist

Password cracking tool

These are software programs that are used to crack user passwords. We already looked at a similar tool in the above example on password strengths. The website www.md5this.com uses a rainbow table to crack passwords. We will now look at some of the commonly used tools

John the Ripper

John the Ripper uses the command prompt to crack passwords. This makes it suitable for advanced users who are comfortable working with commands. It uses to wordlist to crack passwords. The program is free, but the word list has to be bought. It has free alternative word lists that you can use. Visit the product website http://www.openwall.com/john/ for more information and how to use it.

Cain & Abel

Cain & Abel runs on windows. It is used to recover passwords for user accounts, recovery of Microsoft Access passwords; networking sniffing, etc. Unlike John the Ripper, Cain & Abel uses a graphic user interface. It is very common among newbies and script kiddies because of its simplicity of use. Visit the product website http://www.softpedia.com/get/Security/Decrypting-Decoding/Cain-and-Abel.shtml for more information and how to use it.

Ophcrack

Ophcrack is a cross-platform Windows password cracker that uses rainbow tables to crack passwords. It runs on Windows, Linux and Mac OS. It also has a module for brute force attacks among other features. Visit the product website http://ophcrack.sourceforge.net/ for more information and how to use it.

Password Cracking Counter Measures

• An organization can use the following methods to reduce the chances of the passwords been cracked
• Avoid short and easily predicable passwords
• Avoid using passwords with predictable patterns such as 11552266.
• Passwords stored in the database must always be encrypted. For md5 encryptions, its better to salt the password hashes before storing them. Salting involves adding some word to the provided password before creating the hash.
• Most registration systems have password strength indicators, organizations must adopt policies that favor high password strength numbers.

Hacking Activity: Hack Now!

In this practical scenario, we are going to crack Windows account with a simple password. Windows uses NTLM hashes to encrypt passwords. We will use the NTLM cracker tool in Cain and Abel to do that.

Cain and Abel cracker can be used to crack passwords using;

• Dictionary attack
• Brute force
• Cryptanalysis

We will use the dictionary attack in this example. You will need to download the dictionary attack wordlist here 10k-Most-Common.zip

For this demonstration, we have created an account called Accounts with the password qwerty on Windows 7.

Password cracking steps

• Open Cain and Abel, you will get the following main screen

• Make sure the cracker tab is selected as shown above
• Click on the Add button on the toolbar.

• The following dialog window will appear

• The local user accounts will be displayed as follows. Note the results shown will be of the user accounts on your local machine.

• Right click on the account you want to crack. For this tutorial, we will use Accounts as the user account.

• The following screen will appear

• Right click on the dictionary section and select Add to list menu as shown above
• Browse to the 10k most common.txt file that you just downloaded

• Click on start button
• If the user used a simple password like qwerty, then you should be able to get the following results.

• Note: the time taken to crack the password depends on the password strength, complexity and processing power of your machine.
• If the password is not cracked using a dictionary attack, you can try brute force or cryptanalysis attacks.

Summary

• Password cracking is the art of recovering stored or transmitted passwords.
• Password strength is determined by the length, complexity, and unpredictability of a password value.
• Common password techniques include dictionary attacks, brute force, rainbow tables, spidering and cracking.
• Password cracking tools simplify the process of cracking passwords.

Some PDFs are encrypted with a password, which you’ll need to enter each time you want to view the document. You can remove the password to save yourself some inconvenience if you’re keeping the PDF in a secure location.

We’ll cover two ways to do this here: A convenient trick that works in all operating systems with applications you already have, and the official method that requires Adobe Acrobat. Both methods assume you know the password to the encrypted PDF file. Unfortunately, there’s no easy way to remove a password if you don’t know it.

A Convenient Trick: Print to PDF

RELATED:How to Print to PDF on Any Computer, Smartphone, or Tablet

This may seem a little silly, but you can easily and conveniently remove the password from a PDF file by opening it and printing it to a new PDF. Your system will create a duplicate copy of the PDF, and that duplicate copy won’t have a password.

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This trick will only work if the PDF doesn’t have any printing restrictions. However, many PDF files are just password-protected to provide encryption and can be printed normally once you provide the password.

You can do this in a few ways. If you use Chrome on Windows, macOS, Linux, or Chrome OS, you can do it right through your browser. First, open the PDF document and provide the password it requires. Click the “Print” button on the PDF toolbar while viewing the password-protected document.

Click the “Change” button under Destination and select “Save as PDF”. Click the “Save” button and you’ll be prompted to provide a name and location for your new PDF. Your new PDF will contain the same content as the original PDF, but won’t be password-protected.

This method will work in Chrome on any operating system, but you can perform the same trick with other applications and PDF printers. For example, Windows 10 includes a PDF printer, which means you can do this in Microsoft Edge or any other PDF viewer on Windows.

For example, open a protected PDF document in Microsoft Edge and provide the password to view it. Click the “Print” button on the PDF viewer toolbar after you have.

Select the “Microsoft Print to PDF” printer and click “Print”. You’ll be prompted to choose a name and location for your new PDF file.

You can do this trick in any PDF viewer on Windows 10. Just select the “Microsoft Print to PDF” printer. On older versions of Windows, you’ll need to install a third-party PDF printer before you can perform this trick (or just use Chrome).

Crack Pdf Security Password Free

This method also works in other operating systems. For example, on a Mac, you can do this with Preview, or any other PDF viewer and the built-in PDF printing feature.

First, open the protected document in Preview and provide the password it requires. Click File > Print to open the print dialog.

Click the “PDF” menu button at the bottom of the print dialog and select “Save as PDF”. Enter a file name and location for your new PDF file when prompted. The new PDF file will have the same contents as the original, but no password.

Note: Due to the printing process, the resulting PDF won’t have selectable text. if you need to copy text from the PDF, you must re-open the original password-protected PDF and copy text from there. You could also use optical character recognition (OCR) software on the unprotected PDF.

The Official Method: Use Adobe Acrobat Pro

Crack Pdf Security Password Change

You can also do this the official way with Adobe Acrobat Pro, a paid application. This is a different program from the free Adobe Acrobat Reader PDF viewer that most people have. Adobe offers a week-long free trial of Acrobat Pro. Adobe Acrobat Pro will work even if the PDF has printing restrictions, and can’t be printed in other applications using the above trick.

Open the PDF file in Adobe Acrobat Pro and provide its password to view it. Click the lock icon at the left side of the window and click “Permission Details”. You can also click File > Properties and click the “Security” tab.

Click the “Security Method” box, select “No Security”, and click “OK” to remove the password.

Click File > Save to save your changes. You can also just close the Adobe Acrobat Pro DC window and you’ll be prompted to save your changes. Once you have, the password will be removed from the original PDF file.

Remove Pdf Password Security

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Crack Pdf Security Password

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