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Re: how to protect name servers against cache corruption
From: Deepak Jain <deepak () jain com>
Date: Wed, 30 Jul 1997 16:02:04 -0400 (EDT)

Wouldn't a behavior like this be able to be used to bring name servers 
down by simply killing CPU time? 


On 30 Jul 1997 tqbf () smtp enteract com wrote:

In article <19970730001246.22933 () netmonger net>, you wrote:
_details_.  Paul has written papers on DNS security, along with BIND
itself, and I'm inclined to believe him when he says there are no more
trivial fixes.  If you know of one, why don't you share it?  I'm not

Fair enough.

Here's a simple piece of input. If BIND 8.1.1 receives a DNS query
response with an invalid query ID, it logs it and drops the packet.
However, the invalid query ID is evidence of an attack in progress. Why
doesn't BIND parse the packet, find out what question is being answered,
and immediately re-issue the query with a different ID?

In other words, it's possible for BIND to detect that it is under attack
(in a response-forged query-ID guessing situation). BIND doesn't do
anything about this. Why?

Just the simplest suggestion I can come up with (without having this go
into multiple pages) to convey the idea that I am trying to be
constructive here. 

I'm not sure this is the appropriate forum for this discussion 
(*copout*Ididn'tstartthisthread*copout*), but if you want further details
as to my harebrained suggestions, I'm happy to give them!

Thomas Ptacek at EnterAct, L.L.C., Chicago, IL [tqbf () enteract com]
exit(main(kfp->kargc, argv, environ));

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