Breaking into a computer is an illegal activity but it does help to know how to re-access your own equipment.  So, this post is for informational and ethical purposes only! This how-to covers three OS we use and the methods to crack the log-in passwords.

Windows

For Windows OS, Ophcrack is the tool of choice. It is a free Windows Password cracker based on Rainbow Tables. It has a GUI which makes it easier to run. The software can decipher passwords up to 14 characters in length in a quick 10 seconds.

To use Ophcrack one needs to download the Ophcrack ISO and burn it to a CD (or load it via a USB drive). Run the CD by loading it in the tray and restarting the computer with the power switch. Switch to the BIOS options and set the computer to boot from the CD Drive. The computer boots up and reads the Ophcrack CD which then proceeds to break the password. Use this password to log into the machine.

Ophcrack is a multi-platform software and so can be used for Mac and Linux too.

Mac OS X

Apart from Ophcrack, another simple method involves using the Mac OS X installation CD (for v10.4). Insert and reboot to display UTILITIES. Choose RESET PASSWORD to get a new one. Login using this password. To reset the password in Mac OS X 10.5, reboot the computer and press COMMAND + S.

At the prompt type in:

sck -fy
mount -uw /
launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist
dscl . -passwd /Users/UserName newpassword

Login with the new reset password.

Linux

Power on the computer, press the ESC key and on the boot loader (GRUB) screen select the ‘Recovery Mode’. Press the ‘B’ Key to enter the single user mode. At the default prompt, type in ‘passwd’ and key in your new password. For access to a single account on the system type ‘passwd username’ replacing ‘username’ with the login name for the account you would reset the password for.

A lesson in cracking is also a lesson in security. Joe Tech’s article advocates the use of encryption (Blowfish or AES-128) as a failsafe against password breach.

Is ethical hacking for you? Check out these HacknMod tutorials:

• Top 15 Vital Hacking Software and Tools
• How to Hack WEP using a Mac or Linux
• Encrypt your USB Drive

Holding a compressed air can upside down creates extreme cooling of minus 50 degrees Celsius.  Spray this on memory and the stored data fades five times slower than it would naturally.  A full experiment conducted by Princeton exploits this little known property.  “(Memory is) not immediately erased, and their contents remain for malicious (or forensic) acquisition of usable full-system memory images.”

• Check out the experiment’s research paper.
• Learn more though brief pictorial documentation.
• Watch the full demo video: