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How to get into a Linux system with a lost root password
From SecurityBulletins.com
Written by Doug Spencer 11/19/2006
There are a couple of ways to get into a Linux system where you have lost the root password, if you have physical access to the machine.
The first is easy if you don't have a password on the boot loader.
- Reboot the system.
- Indicate to the boot manager (GRUB, LILO, etc) that you want to edit the boot command
- Add "init=/bin/sh" to the boot command as a kernel parameter.
- Boot the system. It will start up into the shell. You can then update the root password to something you know.
The second is the standard way of recovering from a lost password on a UNIX system:
- Boot from CD-ROM, network, or other media. Start in single user mode from this media.
- Once you have a command prompt in single user mode, mount your root device to /mnt
- Edit the password in /mnt/etc/passwd or /mnt/etc/shadow as the case may be.
- Save the changes. Run 'sync" to synchronize the disks. Change directory to /. Run "umount /mnt"
- Reboot from your standard root disk and login
Categories: Linux | UNIX | Operating Systems | Security
