Re: Lost root access

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On 03/02/2011 14:40, Rafa Griman wrote:
Hi :)

On Wed, Feb 2, 2011 at 3:44 PM, James Bensley<jwbensley@xxxxxxxxx>  wrote:
So on a virtual server the root password was no longer working (as in
I couldn't ssh in anymore). Only I and one other know it and neither
of us have changed it. No other account had the correct privileges to
correct this so I'm wondering, if I had mounted that vdi as a
secondary device on another VM, browsed the file system and delete
/etc/shadow would this have wiped all users passwords meaning I could
regain access again?

(This is past tense because its sorted now but I'm curious if this
would have worked? And if not, what could I have done?).

As the other said: DON'T delete /etc/shadow.

Someone also mentioned you could modify the hash in /etc/shadow. This
will work if you are root or have the right permissions with sudo.

If you can reboot the system, what really works great is passing the
following option to the kernel on the lilo/grub screen when the system
boots:

      init=/bin/bash

This will give you a shell without being asked for a password (unless
the sys admin has done his homework ;) Now that you have shell access
... you are in charge so you can:

      - mount the / partition and chroot

      - edit /etc/shadow and delete the password hash

      - whatever you can imagine ... you decide ;)

That would do it... There is single-user-mode (runlevel 1), just add the word single to the kernel parameters line before bootup

It will give you the same result and mount stuff without the need to chroot etc...


--
Best Regards,

Giles Coochey
NetSecSpec Ltd
NL T-Systems Mobile: +31 681 265 086
NL Mobile: +31 626 508 131
GIB Mobile: +350 5401 6693
Email/MSN/Live Messenger: giles@xxxxxxxxxxx
Skype: gilescoochey



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