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Date:      Wed, 22 May 1996 16:48:55 -0500 (CDT)
From:      "Brett L. Hawn" <blh@nol.net>
To:        "Charles C. Figueiredo" <marxx@apocalypse.superlink.net>
Cc:        current@freebsd.org
Subject:   Re: freebsd + synfloods + ip spoofing (fwd)
Message-ID:  <Pine.SOL.3.93.960522164358.17152B-100000@dazed.nol.net>
In-Reply-To: <Pine.BSF.3.91.960522134454.3698H-100000@apocalypse.superlink.net>

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On Wed, 22 May 1996, Charles C. Figueiredo wrote:

> 	FreeBSD has an excellent tcp sequence prediction system, read your 
> /usr/src/sys/netinet, then go read Solaris 2.5's tcp.c and compare.
> 	Look at tcp_random18() for example (a macro). I'de also like to know 
> what you were attempting w/ TCP sequence prediction, if it was just how 
> hard it was to hose the system w/ SYN bits, that's irrelevant to our 
> number generator and the reliability of the implementation. That's 
> dependant on the fact that the system is 4.4BSD based, which there's 
> nothing wrong with. Now, if you're going to tell me that you tried to 
> exploit r* services using tcp sequence prediction through port 513, well 
> wrappers take care of that, I'de like to see you sequence a full-duplex 
> connection based service, and prove FreeBSD cannot handle just as well as 
> any other Unix. I want to know what you're doing w/ your experiments. 
> You're merely giving me lists of stuff that's known by everyone.


Now I see where you dug the port 513 out of, you're the one who mentioned
it, not me. 

Ok, lets see here, right off the top of my brain I could easily spoof you on
IRC and cause you a great deal of pain (having been the victim of one such
spoof I can tell you just how much pain it can cause). Next down the line
would be 'secure' systems that rely on IP/FQDN for their interaction, I
don't need a full duplex connection, all I need to do is get on and do what
I mean to do. So I can't see whats coming back, if I have a well thought out
plan its my guess that I don't need to see whats coming back. The idea is
not to create a full duplex connection, the idea is to 1: knock you out of
service, 2: disrupt your service, 3: connect long enough one way to get
something done that will allow me to sneak in via a new backdoor, 4: lord
only knows what else those minds which are more creative than I have though
of.

Brett




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