Reset root password!!

First thing, don’t think this is a flaw in linux. This is not. This is only possible if you are given the system physically and u are allowed hands on before the booting process.

Here it goes,

1. Start your computer. At the grub screen press ‘e’ on ubuntu os selection.
you get a screen with the kernel and initrd choices.
select the kernel choice and press e.
you will get a line as follows

/boot/vmlinuz-2.6.24-19-generic root=UUID=75058396-0925-491c-badc-d621ea98bf1b ro quiet splash
my kernel is 2.6.24-19, the line will not be exactly same as in yours. just similar.

2. Change it to as follows.
/boot/vmlinuz-2.6.24-19-generic root=UUID=75058396-0925-491c-badc-d621ea98bf1b rw init=/bin/bash

make sure you change ro to rw and remove quite and splash
and add the init process as bash.
then press enter key .

3. then select the kernel that we just edited and press ‘b’ to boot into a root terminal without any authentication.
type in the command passwd
and enter the new root password.

if you want to reset the password of some other users just type su username from the root teminal and use the passwd command to change the password.

Now reboot the system and log with the new passwds.
<<<<<>>>>>

Being root (su root) – No more sudo.

After the ubuntu installation the default user is a sudo user.

Log into that user and type

$ sudo -i

and the password of the user.

now u get a “root” terminal ( inverted comma was to differentiate between the real root and sudo “root”.)

type the command

$ passwd
Enter new UNIX password:
Retype new UNIX password: