Re: Local DoS in kernel 2.6.26

[David Cottrill NCH Software <david.cottrill@nchsoftware.com>]

It may chew up an old computer but a new one won't really do more than 
sniffle.

It goes on an endless loop sending short messages to itself which aren't 
very long. If you wanted to kill a modern computer with that script 
you'd have to set ma=some large number.

It can't kill off a modern multiprocessor CPUs because it is a single 
process, you'd need a forkbomb to do that.
It can't fill RAM because modern computers use more than that program 
was made to absorb.

To kill off a computer quickly:
step one: ":(){ :|:& };:"
step two: reboot because your machine has stopped responding

David.



surreal wrote:
> I just caught hold of a C source code from 2005. This code is a local DoS
> which fills up the entire memory on Linux 2.6.N kernels.
>
> At that time, I used Fedora Core 4 and a pentium 4 machine with 512 MB ram.
> After compiling and running this program on the old machine, it used to hang
> within 40 seconds.
>
> I compiled and ran this program on a test machine having Dual Core CPU, 2 GB
> ram and Debian Lenny to see if this code holds good today.
>
> I saw that RAM wasent running out, but the CPU usage was 100%. I didnt wait
> for computer to hang, but I think this code is dangerous and can be used for
> malicious intentions.
>
> I am sending the code so that we can prevent bad use of it. It still has
> potential of a local DoS. I hope kernel hackers might get interested in
> this.
>
> This code isent tested on AMD 64 bit kernel, but on a 2.6.26 stable kernel.
>
> The C code is attached with this mail.
>
> 800df127fbcb5552a455b6742b62bfe0  mseak.c
>
> Just gcc mseak.c -o mseak; mseak & to see the effects.
>
>
>   


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