More info on Kon Boot is below, but in simplistic terms you can boot of the ISO via floppy, cd, or usb and Kon Boot will analyse the Linux or Windows kernel during the boot process. You can then simply enter with a “blank” password at the normal login process and your on as admin. Obviously this will not give you the password, it is simply a bypass mechanism, but I can certainly see how this will be handy, and could be a handly alternative to something like Ophcrack.
Obviously this will raise some concerns, so using techniques such as using a bios password, hard disk password, total drive encryption will add some hurdles in allowing this type of software to be used. That said its a great tool, and well worth experimenting with.
Kon-Boot is an prototype piece of software which allows to change contents of a linux kernel (and now Windows kernel also!!!) on the fly (while booting). In the current compilation state it allows to log into a linux system as ‘root’ user without typing the correct password or to elevate privileges from current user to root. For Windows systems it allows to enter any password protected profile without any knowledge of the password. It was acctually started as silly project of mine, which was born from my never-ending memory problems Secondly it was mainly created for Ubuntu, later i have made few add-ons to cover some other linux distributions. Finally, please consider this is my first linux project so far Entire Kon-Boot was written in pure x86 assembly, using old grandpa-geezer TASM 4.0.
Updated – 30-6-2009. KonBoot can now Reset the Windows and Linux passwords:
No special usage instructions are required for Windows users, just boot from Kon-Boot CD/Floppy, select your profile and put any password you want. You lost your password? Now it doesnt matter at all.
Or read more here.