Great Circle Associates Firewalls
(March 1996)
 

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Subject: Re: CloakingSoftware(tm)
From: "Jim Leo" <ADMIN @ everett . pitt . cc . nc . us>
Organization: Pitt Community College
Date: Thu, 28 Mar 1996 12:09:16 EST5EDT
To: "Frank O'Dwyer" <fod @ fws . ilo . dec . com>
Cc: firewalls @ greatcircle . com
Reply-to: admin @ everett . pitt . cc . nc . us

On 26 Mar 96 at 19:57, Frank O'Dwyer wrote concerning 
CloakingSoftware(tm)

> 
> > This makes them more vulnerable by
> > definition (they can be "seen" by the network components on the trusted and
> > untrusted sides). A properly configured transparent MS-DOS firewall without
> > an actual IP stack is simply not as vulnerable - you can't see it and you
> > can't attack it in traditional manner(s) in which firewall systems are
> > attacked,  including those based on NT and W95.
> 
> Again I must take issue with this 'you can't see it, so it's not
> as vulnerable as visible systems' suggestion.  It just isn't so,
> and I think I can prove it.  Consider:
> 
> If invisibility is so good, why stop with the firewall?  Make ALL your
> hosts invisible, then you won't even need a firewall.  Here's how
> you do it: Simply put an extra network card in all of your hosts, and put 
> my CloakingDevice(tm) ($100 to you :-) behind (yes, behind) each host.  
> You'll need to replace your host stack with my CloakingSoftware(tm) too, of
> course, but we'll come back to that.   
> 
> What the CloakingDevice does is very simple.  A dedicated piece of
> miniaturised hardware like a T-shaped terminator, it assumes your host's
> current IP address and responds to every packet directed at it with 
> 'host unreachable'.  Obviously, you can't attack the CloakingDevice, 
> since it does hardly anything and runs no services and no OS.  Just
> enough to respond 'host unreachable', nothing else. 
> 
> The really clever part is my CloakingSoftware, which runs on 
> each of your hosts and only costs $200 for a single user licence. 
> (Pretty cheap, since it obliterates all your security worries. :-)  
> The CloakingSoftware runs in kernel mode and bridges ALL packets 
> to the CloakingDevice behind it. The CloakingDevice responds with 
> host unreachable (what else?) and this response is also bridged on
> the way back by the CloakingSoftware, which examines the response 
> prior to bridging it. 
> 
> Now because the CloakingSoftware is a super smart bridge and thus
> stateful, it knows just how to rewrite the host unreachable packet so 
> that it appears just like part of a http response, telnet session, or 
> whatever would be most appropriate to the particular original packet the 
> CloakingDevice didn't respond to.  To a client, it looks like your 
> host is giving service as usual but of course your host has no IP stack and
> only responds to packets from the super secure CloakingDevice.  
> It doesn't listen to clients at all. :-)  And the CloakingDevice doesn't
> offer service at all, so that's safe too.  
> 
> Obviously, with this setup ALL your systems are secure.  You can't 
> attack any of them because none of them are there.  Your hosts don't 
> respond to any packet directed at them (they bridge everything to the
> CloakingDevice).  The CloakingDevice doesn't respond to any packet
> directed at it (it sends host unreachable).  Yet, even though your 
> whole network is not visible, all of your current services still look
> to be there!  Not only that, now  everything from your corporate database 
> to your web server is running in _kernel_ mode, _beneath_ all the weaker 
> OS stuff.  Plus, since you don't need the firewall box any more, you can 
> now run something _useful_ on that box.  Hooray for CloakingSoftware!
> 
> Moral;  don't listen to what they say.  Watch their hands. ;-)
> 
> Cheers,
> Frank O'Dwyer.
> 
> (P.S. Not attacking the DOS-based approach, btw - that's fine.
> it's only the invisibility pitch that I take issue with).
> 
> (P.P.S no, this is not a product announcement. I don't speak
> for DEC :-)  

Dawgone it I could have sworn the pea was under the middle shell...

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