Password cracking doesn't have to involve fancy tools, but it's a fairly tedious process. If the target doesn't lock you out after a specific number of tries, you can spend an infinite amount of time trying every combination of alphanumeric characters. It's just a question of time and bandwidth before you break into a system.
The most common passwords found are password, root, administrator, admin, operator, demo, test, webmaster, backup, guest, trial, member, private, beta, [company_name] or [known_username].
There are three basic types of password cracking tests that can be automated with tools:
- Dictionary - A file of words is run against user accounts, and if the password is a simple word, it can be found pretty quickly.
- Hybrid - A common method utilized by users to change passwords is to add a number or symbol to the end. A hybrid attack works like a dictionary attack, but adds simple numbers or symbols to the password attempt.
- Brute force - The most time-consuming, but comprehensive way to crack a password. Every combination of character is tried until the password is broken.
Some common Web password cracking tools are:
- Brutus is a password cracking tool that can perform both dictionary attacks and brute force attacks where passwords are randomly generated from a given character. Brutus can crack the multiple authentication types, HTTP (Basic authentication, HTML Form/CGI), POP3, FTP, SMB and Telnet.
- WebCracker is a simple tool that takes text lists of usernames and passwords, and uses them as dictionaries to implement basic authentication password guessing.
- ObiWan is a Web password cracking tool that can work through a proxy. ObiWan uses wordlists and alternations of numeric or alpha-numeric characters as possible passwords.
Ethical hacking tools and techniques
About the author
Russell Dean Vines is a bestselling author, Chief Security Advisor for Gotham Technology Group, LLC, and former President of the RDV Group. His most recent book is The CISSP and CAP Prep Guide, published by John S. Wiley and Sons. He is available to answer your security threat questions via Ask the Expert.
This was first published in April 2007