[Chester LUG] "Recovering" (SUSE) (root) passwords

[Daryl Whelan]

Doesn't single-user mode prompt for a root password?
My trick for recovering from a lost root password was changing the 
kernel command line to init=/bin/bash
(i.e. just kernel (hdX,X)/boot/vmlinuz root=/dev/hdXX init=/bin/bash)

YMMV with this tactic though. So long as the drivers for your
HDD and controller are compiled into the kernel, not as modules,
it will work just fine. The only downside is it skips the whole init
process, so none of your boot scripts work.
I've got this to work on several different versions of Slackware,
a couple of Gentoo installs and an old Ubuntu machine (version 6.10 I think)


> -----Original Message-----
> From: chester-bounces at mailman.lug.org.uk [mailto:chester-
> bounces at mailman.lug.org.uk] On Behalf Of Stuart Burns
> Sent: 26 February 2010 16:18
> To: chester at mailman.lug.org.uk
> Subject: Re: [Chester LUG] "Recovering" (SUSE) (root) passwords
> 
> Alternatively when grub is starting  spacebar and apend 1 to boot line
> abd press b. Will boot into single user mode then use passwd
> 
> Sent from my iPhone
> 
> On 26 Feb 2010, at 16:02, Ben Arnold <iamseawolf at gmail.com> wrote:
> 
> > Afternoon --
> >
> > To follow up with yesterday evening's discussion, here is how to
> > "recover" a root password on an installed SUSE (and other with slight
> > modifications) Linux system. I use inverted commas because one
> doesn't
> > recover it, it is chnaged to something new; likewise, other users' is
> > just removed and re-set.
> >
> > These steps will only apply when GRUB is installed; other boot-
> > loaders, like the one on the CD, need a slightly different process.
> >
> > The process involves starting the system in single-user mode
> > (automatically logging in with the root account), changing root's
> > password and optionally removing the password associated with other
> > local accounts.
> >
> > 1) During boot, enter the GRUB boot-loader screen by pressing Escape.
> > - This is where we select which OS to boot. Many contemporary distros
> > use the 'hiddenmenu' feature, booting the default OS if the user
> > doesn't hit a key within 5secs or so. Catch this time-out and display
> > the GRUB menu proper.
> >
> > 2) Ensure the distro item is selected and press 'E'.
> > - This will display the configuration for booting that particular OS.
> >
> > 3) Highlight the 'kernel' line and hit 'E'
> > - This will edit the individual line of the configuration set.
> >
> > 4) Append to the end of this line the word 'single'
> > - This option, or flag, tells the kernel to start a single-user
> > console, rather than continuing a normal boot process with Init,
> after
> > loading the kernel.
> >
> > 5) At the shell, change root's password with the 'passwd' command.
> > - Single-user mode's single user is root. Double-check the currently-
> > logged in user with the 'whoami' command, or make sure the prompt
> > contains the hash symbol instead of the normal dollar sign.
> >
> > 6) Optionally, edit the /etc/shadow file to remove other users' --
> not
> > root's -- passwords. Remove the 2nd field.
> > - The line should read something similar to:
> > johndoe:$6$imR8AG.G$nK4HHDTraw.w7xN1IHAM5ot1dc:13562:0:99999:7:::
> > johndoe::13562:0:99999:7:::
> > but keep the colons. They're the delimiters that separate each field.
> >
> > - the /etc/shadow file mirrors the list of user accounts found in the
> > /etc/passwd file. When a user attempts to log-in, the password
> entered
> > is hashed and compared to the stored MD5 hash found in /etc/shadow.
> >
> > 7) Restart the system.
> > - The only time you'll have to turn it off and back on again.
> >
> > 8) Log in as root with the new password.
> > - If this is not accepted, reboot in to single-user mode again and
> > re-set it.
> >
> > 9) Change other users' passwords using 'passwd username'
> > - Root, as superuser, can change the passwords of others accounts.
> > Other users, however, can only change theirs; sudo must be used for
> > others.
> >
> > 10) Stick the kettle on.
> >
> > Again, this is a generic process that may be slightly different on
> > SUSE, but it shouldn't. I'm pretty sure there isn't anything that can
> > *totally* knacker up a box, but system-level stuff is always prone to
> > slips :) (Confidence FTW)
> >
> > Hope it helps!
> >
> > --
> >
> > Ben Arnold
> > Chester, UK
> >
> > e: iamseawolf at gmail.com
> > e: ben at seawolfsanctuary.com
> > w: seawolfsanctuary.com
> >
> > nom = { :cookies => :mouth }
> > nom; nom; nom
> > _______________________________________________
> > Chester mailing list
> > Chester at mailman.lug.org.uk
> > https://mailman.lug.org.uk/mailman/listinfo/chester
> 
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