Full Disclosure mailing list archives

Re: ICMP Covert channels question


From: cyberpixl <cyberpixl () gmail com>
Date: Sun, 30 Jan 2005 15:24:02 +0100


No, because non-routeable addresses are...well....non-routeable.  The only
exception to this is *if* the target machine already had a session going
with 33.33.33.33 (and it would obviously be nat'd/pat'd) there is a snort
time frame within with your icmp packet would be delivered because the
firewall is still translating the address/port for that session.

Of course you have to know in advance all those variables, so, since you're
sitting right there, just pound the dern thing with a hammer and be done
with it.  :-)

Paul Schmehl (pauls () utdallas edu)
Adjunct Information Security Officer
The University of Texas at Dallas
AVIEN Founding Member
http://www.utdallas.edu


Well, what i meant was what if i use the networks router as a bounce
host in order to get the packets into the network? If an icmp packet
arrives at routers wan port with a source ip of an internal host will
it send the echoreply to its lan port? I currently haven't got the
chance to test this, but i will as soon as i can. Then, in order to
receive replyes from the host behind the firewall all I'd have to do
is make it send packets to a bounce server outsede the network, like
google.com with source set to my ip (assuming then that the router
freely allows icmp traffic out of the network).
_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.netsys.com/full-disclosure-charter.html


Current thread: