RE: [cobalt-developers] Fwd: CERT Advisory CA-2002-17 Apache WebServer Chunk HandlingVulnerability

["Matthew Nuzum" <cobalt@xxxxxxxxxxxxx>]

> > Our systems are neither running Windows nor are they running 64-bit
unix
> > or linux.
> 
> Yes, but did you read
> http://httpd.apache.org/info/security_bulletin_20020617.txt
> 
> Which states
> 
> In Apache 1.3 the issue causes a stack overflow.  Due to the nature of
> the
> overflow on 32-bit Unix platforms this will cause a segmentation
> violation
> and the child will terminate.
> 
> So if someone wanting to take advantage of the exploit targeted
apaches
> child threads, and was able to execute fast enough it could restrict
or
> limit apaches ability to create child threads that will not be
destroyed
> do to a segmentation fault?

If someone wanted to DOS your webserver, they certainly wouldn't need to
be this fancy.  As a matter of fact, they could probably be more
effective by just swamping your server with requests.

I'll bet you could write a 60K program that could eat up an 8MB apache
child process.  A couple thousand of those would be nothing for a modern
PC to run but would easily cripple a heavy duty server.

Whatever preventive measures protect you from standard DOS and DDOS
attacks should prevent anyone from exploiting this weakness in such a
way.

Matthew Nuzum
www.bearfruit.org
cobalt@xxxxxxxxxxxxx