Vulnerability Development: Re: BitchX /ignore bug

[BlueBoar () THIEVCO COM (Blue Boar)]

Rick Jansen wrote:
> I don't know whether this is the right place to put it, but i'm going to
> anyway :)
Yup, and probably Bugtraq, too.

> Because of a simple /invite nickname #%s%s%s%s%s%s%s%s%s, BitchX will
> segfault and coredump. This is a small programming error, you can find a
> patch at this location:
> http://root66.org/karin/BitchX-bug-patch-3-juli-2000.tar.gz by Frank van
> Vliet, alias {}.
The subject: line says /ignore, I assume this problem only occurs
with /invite?  (I don't use IRC much.  /ignore wouldn't send
anything to the ignored party, would it?)

As a general question for vuln-dev:

I've seen a number of these print string vulnerabilities pop up
lately.  I gather that the programmer writes their printf or equiv
wrong, and these attacks are getting interpreted as formatting strings
somehow.

Can someone explain to me what goes on on a stack level?  Are these
exploitable (pushing code) instead of just crashing?

                                        BB