Is this even possible? I can imagine that for security reasons it might be difficult or impossible.
But can it be done, and how?
Hi
Sure it can…
sudo -i
passwd
–
Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 11.1 x86 Kernel 2.6.27.7-9-pae
up 1 day 12:15, 1 user, load average: 0.48, 0.29, 0.29
GPU GeForce 6600 TE/6200 TE - Driver Version: 177.82
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
And if you mean to do it because you’ve lost it (and cannot therefore
boot nor login which would apply to this forum) you can, while at the
Grub screen, type ‘1’ or ‘S’ or init=/bin/bash and boot and make the
changes necessary.
Good luck.
Malcolm wrote:
>
> Hi
> Sure it can…
>
>
> sudo -i
> passwd
>
>
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Thanks Malcolm, good to see you back.
And if you mean to do it because you’ve lost it (and cannot therefore
boot nor login which would apply to this forum) you can, while at the
Grub screen, type ‘1’ or ‘S’ or init=/bin/bash and boot and make the
changes necessary.Good luck.
Is this secure? This seems way too easy.
Hi
Nothing is secure if you have physical access… password the boot
via the bios and password the bios. Again, one could always remove the
drive 
You can do the same sort of things with a windows machine as well.
–
Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 11.1 x86 Kernel 2.6.27.7-9-pae
up 1 day 14:47, 1 user, load average: 0.10, 0.20, 0.16
GPU GeForce 6600 TE/6200 TE - Driver Version: 177.82
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Exactly… rule #1 of security. Physical access always equals
root/administrator access. There is little you can currently do to make
it any other way. A LiveCD, as mentions, lets you access a complete
windows box without leaving any trace (except that the system was
rebooted, assuming it was up and somebody pulled the plug on it) and
without any filesystem restrictions and without SAM protection…
Good luck.
Malcolm wrote:
>
> Hi
> Nothing is secure if you have physical access… password the boot
> via the bios and password the bios. Again, one could always remove the
> drive
>
> You can do the same sort of things with a windows machine as well.
>
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Can a Live CD also access partitions on an otherwise secured Linux machine?
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
If you have physical access any number of ways can access any system…
period.
Good luck.
foresthill wrote:
> Can a Live CD also access partitions on an otherwise secured Linux
> machine?
>
>
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Hi
For sure, just use the mount command if they aren’t already mounted.
–
Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 11.1 x86 Kernel 2.6.27.7-9-pae
up 0:19, 1 user, load average: 0.46, 0.43, 0.36
GPU GeForce 6600 TE/6200 TE - Driver Version: 177.82
So hacking issues aside, a live CD might be useful for retrieving otherwise lost files from a trashed installation. I guess I should keep one of these live CD’s handy.
Thanks for advancing my Linux knowledge by a few very useful pages, maybe even a whole chapter.
Hi
Just the install DVD is enough, boot from that and go to rescue mode.
Enter root and hit enter when it asks for the password and your ready
to go. Unless you need a GUI
Best if you can teach yourself via the CLI on what to do and make
notes. I’m sure one day you will need to use it…
–
Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 11.1 x86 Kernel 2.6.27.7-9-pae
up 1:00, 1 user, load average: 2.61, 1.01, 0.40
GPU GeForce 6600 TE/6200 TE - Driver Version: 177.82
If you haven’t set a boot loader password then anyone who has physical access to your machine can change your root password without knowing root password. 
hey, I opensuse users from Indonesia, I successfully to reset the password using the rescue disk, thank you - Cara Reset Password Root Opensuse 11.3
On Thu, 15 Sep 2011 03:46:03 +0000, c1p1 wrote:
> hey, I opensuse users from Indonesia, I successfully to reset the
> password using the rescue disk, thank you - ‘Cara Reset Password Root
> Opensuse 11.3’ (http://tinyurl.com/42ekcf8)
That’s an interesting solution, but it really isn’t necessary to copy the
hash from one user to another - you can boot the rescue system, mount the
root filesystem on the hard drive, chroot to it, and run the passwd
command.
No need to mess around with copying password hashes in the passwd or
shadow files.
Jim
Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C
Hi,
I have a further question on this.
I accept that, as soon as a bad guy gets physical access to my machine, the data (unless separately encrypted) is not safe and, notably, the root password can be changed without further ado.
However, I DO hope that the bad guy will NOT be able to get the old root password - he can only set a new one but not know the old one.
Is this correct?
TIA
Lenwolf
> hey, I opensuse users from Indonesia,
-=WELCOME=- first time poster!!
Have a lot of fun!
–
DD
openSUSE®, the “German Automobiles” of operating systems
On 2011-09-15 08:26, lenwolf wrote:
>
> Hi,
>
> I have a further question on this.
>
> I accept that, as soon as a bad guy gets physical access to my machine,
> the data (unless separately encrypted) is not safe and, notably, the
> root password can be changed without further ado.
If the encrypted data was mounted, it is not safe.
>
> However, I DO hope that the bad guy will NOT be able to get the old
> root password - he can only set a new one but not know the old one.
>
> Is this correct?
Computationally difficult.
–
Cheers / Saludos,
Carlos E. R.
(from 11.4 x86_64 “Celadon” at Telcontar)
OK, that seems logical.
(I was more thinking of a machine that was switched off when the hypothetical bad guy got at it, but I didn’t specify this - my bad).
Which I take to mean that he can get at the encrypted password and would then need to break the encryption.
Thanks for your answer.
Lenwolf
On 2011-09-15 12:06, lenwolf wrote:
>> Computationally difficult.
>> >
> Which I take to mean that he can get at the encrypted password and
> would then need to break the encryption.
Exactly. I’m sure that there is a procedure or program somewhere around to
try break the password; but it must be quite difficult to break, or the
encryption method would have been changed ages ago.
–
Cheers / Saludos,
Carlos E. R.
(from 11.4 x86_64 “Celadon” at Telcontar)
On Thu, 15 Sep 2011 06:26:03 +0000, lenwolf wrote:
> Hi,
>
> I have a further question on this.
>
> I accept that, as soon as a bad guy gets physical access to my machine,
> the data (unless separately encrypted) is not safe and, notably, the
> root password can be changed without further ado.
>
> However, I DO hope that the bad guy will NOT be able to get the old root
> password - he can only set a new one but not know the old one.
>
> Is this correct?
This is not entirely correct. If one grabs the appropriate files, one
can do an offline brute-force attack on those files, assuming local
authentication is being used on the system.
If the system is compromised, if that password is used elsewhere, it
should be changed. Never assume that a password that’s been compromised
is safe to continue to use.
Jim
–
Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C