Re: Firewall without network Stack (SUMMARY)

From: Kyle Wheeler (memoryhole@cheerful.com)
Date: 09/29/01


Message-Id: <200109291933.f8TJXUOh517431@oak.cats.ohiou.edu>
Date: Sat, 29 Sep 2001 15:33:29 -0400
From: Kyle Wheeler <memoryhole@cheerful.com>
To: Focus on Linux Mailing List <FOCUS-LINUX@SECURITYFOCUS.COM>
Subject: Re: Firewall without network Stack (SUMMARY)

With the help of a few people, I found what I was looking for (and a bit
more, actually). For anyone who is interested, the software project I
had seen and was trying to find again is called "HogWash"
(http://hogwash.sourceforge.net/).

> What's the point of this, beside slowing down everything?

Well, among other things, the firewall wouldn't have an IP address on
the internet - and thus would be much harder to attack because a hacker
can't make a direct connection to it. For another, you can filter based
on the content of the packets, or the pattern of packets - for example,
theoretically, packets that are part of an http connection request that
contain the string "default.ida" and who's GET string is longer than a
certain length could be denied.

According to the HogWash web page, "Instead of closing ports like a
traditional firewall, it drops or modifies specific packets based on a
signature match."

A few people suggested looking into the SOCK_PACKET interface, and maybe
the SOCK_RAW interface... I'm not sure of the difference or the
specifics, but I'll be looking into them as well.

Thanks, everyone!
~Kyle Wheeler

--
I've finally learned what "upward compatable" means. It means we get to 
keep all our old mistakes.
-- Dennie van Tassel



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