[nsp-sec] Potential TCP / IP vulnerabilities announcedmidOctober - Outpost24 interview

[David Freedman]

Just a quick look at the FBSD 4 kernel confirms that this uses a lower value of 296

no idea about anything else closed source.

Dave.

------------------------------------------------
David Freedman
Group Network Engineering 
Claranet Limited
http://www.clara.net



-----Original Message-----
From: Florian Weimer [mailto:fweimer at bfk.de]
Sent: Sat 10/4/2008 15:30
To: David Freedman
Cc: Chris Morrow; nsp-security at puck.nether.net
Subject: Re: [nsp-sec] Potential TCP / IP vulnerabilities announcedmidOctober - Outpost24 interview
 
* David Freedman:

> Yes, well, I could sit there spoofing TOOBIG messages
> and make the node send smaller (but more) packets 
> driving its CPU up, surely?

Linux limits the discovered path MTU to something around 550 bytes by
default.  I don't think this has caused any problems, and it limits
the overhead you can introduce.

(Obviously, I totally agree that this issue is worth fixing if your
stack goes down to arbitrary PMTU values.)

-- 
Florian Weimer                <fweimer at bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
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