Re: [PEN-TEST] IP Tunneling over DNS

[Andre Delafontaine <andre.delafontaine () ECHOSTAR COM>]

"Christopher M. Bergeron" wrote:
> I just read an interesting post at slashdot:  http://slashdot.org/article.pl?sid=00/09/10/2230242&mode=thread
>
> theoretically, someone from inside a secure network could tunnel out (ala Trojan) to punch a major hole through a 
> firewall.  Am I understanding this correctly?


Once somebody controls a host inside a network, he can tunnel out using
any protocol the firewall will let through, even if it is outbound only
(i.e. http): Back Orifice will pass data over ICMP, so allowing outgoing
pings through a firewall is sufficient, as long as the ECHO REPLIES can
come back.

Markus Ranum has mentioned that he once implemented an nfs mount of an
internal host's filesystem through a firewall that only passed email:
the internal and external hosts encapsulated IP packets in individual
mails. It was slow, but worked...

Andre
--
             andre.delafontaine at echostar.com

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