Ubuntu Guide For Windows Users: Reset Your Password When You Have Forgotten It
For Windows users, several solutions exist if you have forgotten your password such as creating a password reset disk.
But how about if you are on an unfamiliar system such as Ubuntu (or any Linux distribution) and you forgot your password. Do you know what steps to take to reset your password so you can log back in to your computer?
Unlike Windows, this process is a lot easier.
To get started, just boot your computer and when you see "Loading Grub" press the ESC (Escape) key. If you missed it, just reboot and try again.
Once you see the Grub prompt, press 'e' to enter Edit mode (as shown by the arow in below screen shot).
Next, highlight the line that begins with kernel and press 'e'.
Now, what you see may seem a little odd, but go the very end of the line, hit the space bar once, then type the following command after the word 'splash':
rw init=/bin/bash
and press enter, then b to reboot.
After Ubuntu has restarted, instead of loading the GUI, you will see a passwordless root shell. At the prompt, type the following command and replace 'username' with the name of the account you want to change the password.
passwd username
Type in a new password and retype to verify, once you see the confirmation that your password was updated successfully, reboot.
When GNOME loads enter your new password and you should be good as new again.
Filed under Ubuntu And Linux Tips by Watching The Net
Comments on Ubuntu Guide For Windows Users: Reset Your Password When You Have Forgotten It »
I am not sure why this is considered easier than Windows, but that is a typical comment to make.
Anyway, what if you have ab encrypted rootfs or use SELinux?
@Silver
With Windows, if you don't have another account (with rights to change user account passwords)you either need to create a password reset disk or use a third party utility just to change your password (when you have forgotten it).
Compare that to Linux, the above method is much easier.
As for ab encrypted rootfs or SELinux, I'll need to do some digging if the method can be used.
There's an even easier way: just select the recovery mode option, select "root" (Drop to root shell prompt) and change your password that way. No need to alter any lines or anything of that sort.
How can this be secured against? If I won't forget my password and would rather reinstall than leave root access open this easily?
Isn't that what the "recovery mode" option is for? I haven't used Ubuntu in a while, but on Gentoo that means a root prompt in single user mode. (i.e this)
And to answer Jimmy, there is no way to stop access to the root prompt on your computer (if you have physical access), but you CAN encrypt the hard disk. Then you have to enter a password to boot up at all. There are many howtos on this, but you only want it if you really care about security.
WOW!!!
You guys need some serious help. First of all, yes those will work.
If you don't want people to edit GRUB in this way, then password protect it. This guide goes over using encrypted passwords, but plain text passwords are also possible. The idea is to protect 1. booting into recovery mode, and 2. editing the configuration file.
http://www.debiantutorials.org/content/view/40/227/
I also added a comment in there to explain some things.
The will pretty securely cover GRUB. BUT, I know of a way around this. You can boot to a live CD and change the systems /etc/shadow file which contains system passwords. You can replace any users password with another hash. But once GRUB is locked down, going through that process would be pretty painstaking since you can no longer just wipe the root password and boot into recovery mode.
Anyway, how some of that has been cleared up for you.
No amount of security will help if the attacker has physical access to the machine. There are even ways around drive encryption, especially if the drive is still mounted when the machine is 'attacked'. Boot passwords and BIOS passwords are easily circumvented to even the slightest determination. All you need is a livecd and a screwdriver!
The above shouldn't ever be used unless you really know what you're doing and won't work for encrypted volumes (in most cases you WILL run in to trouble if you set init to a shell, such as the environment not being set up (thus making vim and other editors useless)). Use the recovery mode to properly boot in to single user mode, as it will run through essential init scripts.
On most Linux installs, setting init=/bin/sh will boot with / in read only mode too since remounting it is handled by a init script.
It's called recovery mode for a reason! Use it!