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Date:      Wed, 9 May 2001 11:26:46 -0600 (MDT)
From:      webmaster <russ@mtanet.net>
To:        freebsd-questions@FreeBSD.ORG
Subject:   A new bind vulberability?
Message-ID:  <Pine.BSF.4.21.0105091104540.9798-100000@C1521581-A.BLLNGS1.MT.HOME.COM>

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Hi,

I have two dns servers running freebsd/bind 8.2.3-T6B in which bind
appears to be vulnerable to version questions asked in a certain manner. 
When dig is used in a certain way, and I don't know exactly how not being
at our attacker's terminal, it causes named to exit, signal 11 pretty
effectively DOSing us. Below are entries from the logging we have going
for named and the outputs of uname -a and dig. Please see below and respond
with any suggestions/coments that you think would help.

Begin Log entries and outputs:
===========================================================================
FROM NS1 queries.log

09-May-2001 01:59:00.905
XX+/127.0.0.1/1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0.0.0.0.ip6.int/PTR/IN
09-May-2001 01:59:01.179 XX+/127.0.0.1/0.0.0.127.in-addr.arpa/PTR/IN
09-May-2001 02:05:37.244 XX /64.14.48.132/techout.net/MX/IN
09-May-2001 02:07:33.558 XX /194.236.70.13/version.bind/TXT/CHAOS

[Right after the question above is asked from 194.236.70.13, named exits
the next entries are not until I restart named the next morning at 9:29]

09-May-2001 09:29:32.768 XX /24.0.2.76/mail.lockdoctor.net/A/IN
09-May-2001 09:29:34.726 XX /64.208.134.12/bikemotor.com/A/IN
09-May-2001 09:29:34.857 XX /64.208.134.12/bikemotor.com/MX/IN
09-May-2001 09:29:37.768 XX /24.0.2.76/mail.lockdoctor.net/A/IN
09-May-2001 09:29:39.855 XX /64.208.134.13/bikemotor.com/A/IN

======================================================================

FROM NS2 queries.log

10-May-2001 02:01:18.289 XX+/127.0.0.1/ns2.funkltd.com/AAAA/IN
10-May-2001 02:01:18.290 XX+/127.0.0.1/ns2.funkltd.com.funkltd.com/AAAA/IN
10-May-2001 02:09:20.483 XX /194.236.70.13/version.bind/TXT/CHAOS

[Same thing here]

10-May-2001 10:11:04.062 XX /207.149.226.4/fleetwoodgaming.com/MX/IN
10-May-2001 10:11:36.533 XX /164.58.198.150/www.bikemotor.com/A/IN
10-May-2001 10:14:32.211 XX /4.24.21.198/www.bikemotor.com/A/IN

======================================================================
Output of uname and dig for ns1

uname -a
FreeBSD NS1.funkltd.com 4.2-RELEASE FreeBSD 4.2-RELEASE #0: Mon Feb 19
15:44:12 MST 2001     root@NS1.funkltd.com:/usr/src/sys/compile/NS1SMP3
i386 
----------------------------------------------------------------------
dig @204.212.40.206 version.bind. CHAOS TXT

; <<>> DiG 8.3 <<>> @204.212.40.206 version.bind. CHAOS TXT 
; (1 server found)
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUERY SECTION:
;;      version.bind, type = TXT, class = CHAOS

;; ANSWER SECTION:
VERSION.BIND.           0S CHAOS TXT    "8.2.3-T6B"

;; Total query time: 179 msec
;; FROM: C1521581-A.BLLNGS1.MT.HOME.COM to SERVER: 204.212.40.206
;; WHEN: Wed May  9 11:23:05 2001
;; MSG SIZE  sent: 30  rcvd: 64

======================================================================
Output of uname and dig for ns2:

uname -a
FreeBSD ns2.funkltd.com 4.2-RELEASE FreeBSD 4.2-RELEASE #0: Thu Mar 29
04:59:21 GMT 2001     root@ns2.funkltd.com:/usr/src/sys/compile/GMANSYS
i386

-----------------------------------------------------------------------
dig @204.212.40.207 version.bind. CHAOS TXT

; <<>> DiG 8.3 <<>> @204.212.40.207 version.bind. CHAOS TXT 
; (1 server found)
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUERY SECTION:
;;      version.bind, type = TXT, class = CHAOS

;; ANSWER SECTION:
VERSION.BIND.           0S CHAOS TXT    "8.2.3-T6B"

;; Total query time: 142 msec
;; FROM: C1521581-A.BLLNGS1.MT.HOME.COM to SERVER: 204.212.40.207
;; WHEN: Wed May  9 11:24:20 2001
;; MSG SIZE  sent: 30  rcvd: 64

=========================================================================

End log entries

What do you tink? 

Sincerely,

==================================
 Russ Mummey

 Systems Administrator/IT Manager
 MTANET.NET
 Phone  406.896.0688
 Fax    406.896.0684
 Email  webmaster@mtanet.net
==================================


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