forgot root password or reset root password in Debian
Posted by Admin on September 30th, 2006
If you're new here, you may want to subscribe to my RSS feed. Thanks for visiting!
There are various methods available for resetting a root password.
Boot debian linux into single-user mode
Boot using a boot disk (like knoppix,gnoppix) and edit the password file
Mount the drive on another computer and edit the password file
It is possible to boot a system and log on to the root account without knowing the root password as long as one has access to the console keyboard.
This is a procedure which requires no external boot disks and no change in BIOS boot settings. Here, “Linux” is the label for booting the Linux kernel in the default Debian install.
Solution 1
At the lilo boot screen, as soon as boot: appears (you must press a shift key at this point on some systems to prevent automatic booting and when lilo uses the framebuffer you have to press TAB to see the options you type), enter:
boot: Linux init=/bin/sh
This causes the system to boot the kernel and run /bin/sh instead of its standard init. Now you have gained root privileges and a root shell. Since / is currently mounted read-only and many disk partitions have not been mounted yet, you must do the following to have a reasonably functioning system.
# mount -n -o remount,rw /
# mount -avt nonfs,noproc,nosmbfs
# cd /etc
# vi passwd
# vi shadow
(If the second data field in /etc/passwd is “x” for every username, your system uses shadow passwords, and you must edit /etc/shadow.) To disable the root password, edit the second data field in the password file so that it is empty. Now the system can be rebooted and you can log on as root without a password. When booting into runlevel 1, Debian (at least after Potato) requires a password, which some older distributions did not.
It is a good idea to have a minimal editor in /bin/ in case /usr/ is not accessible.Also consider installing the sash package. When the system becomes unbootable, execute
boot: Linux init=/bin/sash
sash serves as an interactive substitute for sh even when /bin/sh is unusable. It’s statically linked, and includes many standard utilities as built-ins.
Solution 2
Boot from any emergency boot/root disk set. If /dev/hda3 is the original root partition, the following will let one edit the password file just as easily as the above.
# mkdir recovery
# mount /dev/hda3 recovery
# cd recovery/etc
# vi shadow
# vi passwd
Scroll down to the line containing the root user’s information, which looks something like
root:weeWRSF!sfDFs:12581:0:99999:7:::
Delete everything between the first and second colons, so that the line looks like
root::12581:0:99999:7:::
Save the file and exit your editor.Type cd to return to your home directory.
Type umount mountplace to unmount the partition.
#unmount /dev/hda3 recovery
Type reboot to reboot your system
The advantage of this approach over the previous method is one does not need to know the lilo password . But to use it one must be able to access the BIOS setup to allow the system to boot from floppy disk or CD, if that is not already set.
Solution 3
Reseting passwords by mounting on another system and editing the password file is bit more work need to be done.first you need to Shut down the machine after backing up all important data.Now remove you machine hard disk and connect this hard disk as slave drive for another machine(this should be linux OS) and boot this machine.Once the system finishes booting, mount the slave drive’s root partition and edit the password file.If /dev/hda3 is the original root partition, the following will let one edit the password file just as easily as the above.
# mkdir recovery
# mount /dev/hda3 recovery
# cd recovery/etc
# vi shadow
# vi passwd
Scroll down to the line containing the root user’s information, which looks something like
root:weeWRSF!sfDFs:12581:0:99999:7:::
Delete everything between the first and second colons, so that the line looks like
root::12581:0:99999:7:::
Save the file and exit your editor.Type cd to return to your home directory.
Type umount mountplace to unmount the partition.
#unmount /dev/hda3 recovery
Type reboot to reboot your system
If you want to prevent others from resetting your root password you can use two options first one is protect your bootloader with password i.e your GRUB or LILO boot loaders and second one is protect BIOS with password.
January 9th, 2007 at 12:39 pm
Solution 4
boot with livecd (i’m using slackware install)
mkdir /d
mount /dev/hda1 /d
chroot /d
passwd (or passwd root)
type your new password
press Ctrl+Alt+Delete and enjoy
May 16th, 2007 at 9:54 am
I know I’m just one of those newbie in linux and you don’t have time to update the web page every-time.please show me how to do it with grub as it is the most default bootloader.
thanks for hearing me
July 23rd, 2007 at 3:07 pm
Yes you can do it from grub as well:
1. Select the appropriate entry in the grub menu and press ‘e’
2. Select the kernel … line and press ‘e’
3. Append ‘init=/bin/bash’ at the end of line
4. Press ‘b’ to boot
Then you will need to remount the system as rw and use the passwd command to change the pass
February 4th, 2008 at 4:28 pm
Thanks Theo… I’ve added the mount command for the likes of me:
mount -n -o remount,rw /
January 8th, 2009 at 5:43 pm
I have mac os x my girl friend mistakely change the user name and password I did not know where i put my installation disc pls. help
March 20th, 2009 at 5:34 pm
Thanks so much! Helped me out on an old server where the former admin forgot the password or it was changed somehow.
March 20th, 2009 at 5:39 pm
Also, I was just able to use ‘passwd root’ when I got root access using Solution 1, didn’t have to edit any files.
March 24th, 2009 at 8:03 am
For Ubuntu, if you are a member of the admin group, you can simply type:
sudo passwd
Enter your user password and then it will allow you to change the “UNIX” password… su.
July 27th, 2009 at 6:44 am
What Erica just said is valid for more then Ubuntu.. is valid for more distributions.
LX Debian
August 19th, 2009 at 8:06 am
I am using Ubuntu9.4. When I boot it with init=/bin/bash, It comes to root@none:/ and hangs.
need help.