nanog mailing list archives

Re: Cisco vulnerability and dangerous filtering techniques


From: jgraun () comcast net
Date: Tue, 22 Jul 2003 14:58:22 +0000


That is a bit paranoid, but it could happen.  I have not seen anybody do 
anything that intelligent in the past couple of years.  Not to say that there 
arent people out there that couldn't do that but I think many have thought of 
using one exploit to expose another, DDoS is the closest I have seen on any of 
my honeypots.  I have learned many things about what most people will try to 
get into a box from the honeypots, but that is a good point.  Filtering or 
patching should take place on the edge and on the most critical spots on your 
network.

Good Luck

I had a passing thought over the weekend regarding Thursday's cisco
vulnerability and the recent Microsoft holes.

The next worm taking advantage of the latest Windows' vulnerabilities is
more or less inevitable.  Someone somewhere has to be writing it.  So why
not include the cisco exploit in the worm payload?

Based on past history, there will be plenty of vulnerable Windows hosts to
infect with the worm.  I would also guess that there are lots of
organizations and end-users that have cisco devices that haven't patched
their IOS.  Furthermore, I wonder how many people have applied filtering
only at their border?  But packets from an infected host inside the
network wouldn't be stopped by filtering applied only to the external
side.

Basically, if you're filtering access to your interface IP's rather than
upgrading IOS, remember that the internet isn't the only source of danger
to your network.

Adam Maloney
Systems Administrator
Sihope Communications



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