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5.1.2.4 Lab - Password Cracking

The document outlines a lab exercise focused on password cracking using the John the Ripper tool on a Linux system. It provides step-by-step instructions for recovering passwords for four user accounts: Alice, Bob, Eve, and Eric. The lab requires an Ubuntu 16.04 Desktop LTS environment and includes commands for combining password files and cracking the passwords using a predefined dictionary.

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158 views3 pages

5.1.2.4 Lab - Password Cracking

The document outlines a lab exercise focused on password cracking using the John the Ripper tool on a Linux system. It provides step-by-step instructions for recovering passwords for four user accounts: Alice, Bob, Eve, and Eric. The lab requires an Ubuntu 16.04 Desktop LTS environment and includes commands for combining password files and cracking the passwords using a predefined dictionary.

Uploaded by

arvillbach
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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Lab – Password Cracking

Objectives
Use a password cracking tool to recover a user’s password.

Background / Scenario
There are four user accounts, Alice, Bob, Eve, and Eric, on a Linux system. You will recover these passwords
using John the Ripper, an open source password cracking tool.

Required Resources
 PC with Ubuntu 16.04 Desktop LTS installed in a VirtualBox or VMware virtual machine.

Step 1: Open a terminal window in Ubuntu.


a. Log in to Ubuntu using the following credentials:
User: cisco
Password: password

b. Click on the terminal icon to open terminal.

Step 2: Run John the Ripper.


a. At the command prompt, enter the following command to change to the directory where John the Ripper
is located:

HI6041 Information Systems Security


Page 1 of 3
Lab - Password Cracking

cisco@ubuntu:~$ cd ~/Downloads/john-1.8.0/run
b. At the command prompt, enter the following command :
cisco@ubuntu:~/Downloads/john-1.8.0/run$ sudo ./unshadow /etc/passwd
/etc/shadow > mypasswd

This command will combine the /etc/passwd file where user accounts are stored, with the /etc/shadow file
where user passwords are stored, into a new file called “mypasswd”.

Step 3: Recover Passwords.


a. Type the following command in terminal:
cisco@ubuntu:~/Downloads/john-1.8.0/run$ ./john --show mypasswd

As shown above, there are no cracked passwords at this point.


b. At the command prompt, enter the following command:
cisco@ubuntu:~/Downloads/john-1.8.0/run$ ./john --wordlist=password.lst --
rules mypasswd --format=crypt

The program, John the Ripper, uses a predefined dictionary called password.lst with a standard set of
predefined “rules” for handling the dictionary and retrieves all password hashes of both md5crypt and
crypt type.
The results below display the passwords for each account.

HI6041 Information Systems Security


Lab - Password Cracking

c. At the command prompt, enter the following command:


cisco@ubuntu:~/Downloads/john-1.8.0/run$ ./john --show mypasswd

How many passwords were cracked?


____________________________________________________________________________________
References
John the Ripper: http://www.openwall.com/john/

HI6041 Information Systems Security

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