Great Circle Associates Firewalls
(February 1997)
 

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Subject: Re: Port 135 [and other NT attacks] (fwd)
From: Jonathan Wilkins <jwilkins @ secnet . com>
Date: Wed, 12 Feb 1997 17:34:34 -0700
To: Christopher Klaus <cklaus @ iss . net>
Cc: firewalls @ GreatCircle . COM

Chris Klaus posted:
>NT DNS Denial Attack
>
>If an attacker spoofs a response that the DNS never requested, DNS will
>terminate.
>There is an advisory on this available at
http://www.iss.net/lists/general/0118.html
>
>Solution:
>
>Currently, Microsoft is working on a solution.

Here's a little more information on this problem:

there were a few different problems discovered in the DNS that Microsoft
put out.. the first was due to the reception of a response to an query that
was never sent.  [basically any DNS packet with the query/response bit set
to true]

I posted an advisory on this and James Gilroy (the developer of DNS at
microsoft) managed to get a fix out in about a day (an admirable feat for a
vendor).. Unfortunately the fix wasn't complete.. I managed to find another
bug a day or so later.. but once more James put out a patch and this one
has passed a few tests I threw at it.. It is due to be released along with
service pack 3 which is due out this quarter..

you can also get a copy at ftp://rhino.microsoft.com/

this fix is only available for intel, and as I don't have a NT system
running on alpha I haven't confirmed whether or not the alpha version of
DNS is vulnerable.. 

if anyone wants to volunteer a little bit of time we can test it out...

					Jonathan
-=-=-=-=-=-=-=-
Jonathan Wilkins      |  Futuaris   | If only they had used their
jwilkins @
 secnet .
 com   | Non Irresus | terminals for niceness instead
http://www.secnet.com |  Ridebus    | of evil ...-Maxwell Smart

Indexed By Date Previous: Re: [FW1] strange behavior
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From: Gary Hanna <gary @ excalib . com>
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From: "Lack Mr G M" <gml4410 @ ggr . co . uk>
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