On Mon, Apr 02, 2001 at 09:22:32AM -0400, Jonathan Rickman wrote:
> > To repeat, my question is: Is there a tool, or can there be a tool that can
> > create filesystem damage when being a remote, non-privileged user? Let's
> > assume that you can not power down the machine at will, so the tool should
> > be autonomous, that is, not relying on a shutdown or power-failure to do the
> > exact damage (the tool just creating the hard drive activity required to
> > make this damage more probable). Instead, the tool must create the damage
> > itself, even if the machine is perfectly powered and not overloaded.
> >
> > It seems that my previous posts were unclear. I am talking about a remote,
> > non-privileged DoS. No local console, no root access, no floppy access, no
> > power-switch access, no hammer handy.
>
> I think you may be thinking along the lines of the recently publicized
> Stick DoS attack (whether theory or reality is of no consequence here)
> against IDS systems. As it has been said before, once you get that
> far...

Get how far? He's talking about potential file system corruption as a user,
not root with a file system debugger. Pretend UFS corrupted itself when
you touched a file called UFS-SUCKS-BALLS anywhere on the filesystem -
A potential DOS would be to find a hole in a CGI that'll allow the
arbitrary execution of commands (unless you're dealing with super dumb
people, this won't be as root) and touch said file.

Next time server reboots (fake a mail from somebody saying the machine
needs a reboot, or use a new TCP attack to force a panic, whatever)
the machine won't come back up unattended. It is a potential DOS, the
original poster wasn't insane or anything. :)

File systems aren't infallible - I haven't got the advisory to go with it,
but I came across this today...
http://www.oreillynet.com/pub/a/linux/2001/03/27/insecurities.html

UFS and EXT2FS have unexpected functionality - File systems are large structures,
and while operating systems try their best to stop you from messing them
up, we all know you can't be assured that that is the case.

At the very least though, to get to the level where you can start attacking
a file system (intresting idea...) you need to be able to execute arbitrary
commands, you're too abstracted from the filesystem to possibly cause any
damage IMHO. And once you can run arbitrary commands, there's more likely
ways of breaking into a system - It'd be low on my list of potential attacks
were I given an interactive shell. :)

--
Brian Scanlan, Systems Administrator.
Irish Times New Media - http://www.ireland.com

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