how to protect name servers against cache corruption

Wed Jul 30 13:15:35 UTC 1997

On Wed, Jul 30, 1997 at 04:38:59AM -0000, tqbf at smtp.enteract.com wrote:
> >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?

If a copy of BIND _receives_ a query, decides it's bogus, logs it, and
drops it, then a question isn't _being_ answered, it's bing _asked_.

Why _would_ BIND re-issue a query.  it hadn't _issued_ that query in
the first place.  Or, in simpler terms, "huh"?

> 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?

This isn't so much a security bug, but more a lack of a security-enhancing
feature.  It _certainly_ doesn't merit the veiled character assination
you've been using it to justify.

> 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. 

You've failed.

> 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!

Time to move this to bind-workers, no?  Perry, Paul?

Cheers,
-- jra
-- 
Jay R. Ashworth                                                jra at baylink.com
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