How to break root password in Linux (RedHat/CentOS)
Its actually very easy to break a linux server’s root password if you have access to the physical server. Security is actually an illusion, just you need to make your server secure from any kind of threat that is coming from your environment and also your friends.
Here i will describe how to break a linux server’s password in a easy way, if you anyhow forget your root password it can be recovered just some few steps and commands. lets begin…
Step-1: Reboot your system by hard switch or pressing ‘Ctrl+Alt+Del’ or any other way you want. And don’t allow your server to load the OS again, i mean before loading just press arrow keys.
Step-2: Now you need to edit the current entry by pressing ‘e’ button. It will open some scripts in your window.
Step-3: Find the line that starts with ‘linux16’ and navigate your cursor to the end of the line. You can do this by pressing the ‘End’ button or by pressing right arrow until the last character. Now add or append ‘rd.break’ after a space at the end of the line. And press ‘Ctrl+x’ to boot using the modified config.
Step-4: System will appear with command link viewing something like below.
Now you need to remount /sysroot file and give read/write permission.
switch_root:/# mount -o remount,rw /sysroot
switch_root:/# chroot /sysroot
‘chroot’ runs a command or an interactive shell from another directory, and treats that directory as root. It will take you to a new shell like below.
Here you need to give the ‘passwd’ command to give it a new password. it will prompt twice.
sh-4.2# passwd [press enter]
: ******* (123456)
: ******* (123456)
After all these steps the last step is to create a autorelabel executable file which the OS will take to relabel the configuration file. Next just exit from both shell and it will take some time(like 2min) to boot and you can enter with the new password.
sh-4.2# touch /.autorelabel
Wait for 2 minute and Login… Hurreeeh…!!! now access the root with your new password and you can change this with any password you want.