Did you know that default Linux installation is vulnerable?
Linux root password can be broke easily by modifying ‘/etc/shadow’ file.
In Linux/Unix ‘shadow’ file used to store user name, password, account validity period etc.
User password is stored into 3rd column in encrypted form and each column is delimitated by :, e.g.
Only you need to boot up the target system with a live Linux cd ( may be Knopix, backtrack ) and log into the system as root user.
If you empty the 3rd field it implies that no password is set against root account. After modifying the field will look like this,
Try to log into system as root, you will no need of password at all.
Note: You must take a back up copy of ‘/etc/shadow’ file for emergency shadow file recovery.