Root! Root! Root!

Paul Sladen sounder at
Tue Mar 15 10:52:39 UTC 2005

On Tue, 15 Mar 2005, Burgundavia wrote:


> As said above, if someone has physical access to your system, you are
> done. Kaput. No security.

Absolutely correct!

> However, having no root password for single user mode does kind of suck.
> Not for security, but for kids and other non-techical users you might
> accidently select the mode and then seriously mess things up.

What actually happens is that 'sulogin' (Single-User Login) checks is see
there is a 'starred-out' (disabled) root password.  'sulogin' then knows
that 'sudo' is still in operation on the machine and drops you at a command

Can anyone think of possible ways to improve this situation if people think
it might be a problem?

Remember that one of the common uses for Single-User recovery mode is
resetting a forgotten password, or re-enabling a required system component
that the user thought it would be cool to disable.  Any solution cannot
depend on either of these!

Note that for more secure systems (for example a shared datacentre where you
have already removed the CD and floppy drives, unplugged all external USB
ports and poored eproxy over the reset button and keyboard connectors),
there is an option for this one narrow situation:

The Grub password option.  With this on, a password needs entering at the
bootloader stage to select or modify any option except the default.

There is an example near the top of the configuration file:


The same can be done for the BIOS, to prevent an option except booting the
default (Grub from the first Hard-disk).

I didn't know it snowed here!  London, GB

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