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AUSCERT External Security Bulletin Redistribution
AIX named DNS BIND dynamic update denial of service
6 August 2009
AusCERT Security Bulletin Summary
Product: BIND 9
Operating System: AIX
Impact/Access: Denial of Service -- Remote/Unauthenticated
CVE Names: CVE-2009-0696
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IBM SECURITY ADVISORY
First Issued: Wed Aug 5 09:40:52 CDT 2009
The most recent version of this document is available here:
VULNERABILITY: AIX named DNS BIND dynamic update denial of service
PLATFORMS: AIX 5.3, 6.1
SOLUTION: Apply the fix as described below.
THREAT: A remote user can create a denial of service on AIX
DNS servers running BIND.
CERT VU Number: VU#725188
CVE Number: CVE-2009-0696
Reboot required? NO
Protected by FPM? NO
Protected by SED? NO
AIX 'named' is an implementation of BIND (Berkeley Internet Name
Domain) providing server functionality for the Domain Name System
(DNS) Protocol. AIX currently ships and supports three versions
of BIND: 4, 8, and 9.
There is an error in the handling of dynamic update messages in
BIND 9. A crafted update packet from a remote user can cause a
master server to assert and exit. Please see the following for
The successful exploitation of this vulnerability allows a remote,
unauthenticated user to make a master DNS server assert and exit.
The following command is vulnerable:
II. PLATFORM VULNERABILITY ASSESSMENT
To determine if your system is vulnerable, execute the following
lslpp -L bos.net.tcp.server
The following fileset levels are vulnerable:
AIX Fileset Lower Level Upper Level
bos.net.tcp.server 126.96.36.199 188.8.131.52
bos.net.tcp.server 184.108.40.206 220.127.116.11
bos.net.tcp.server 18.104.22.168 22.214.171.124
bos.net.tcp.server 126.96.36.199 188.8.131.52
bos.net.tcp.server 184.108.40.206 220.127.116.11
bos.net.tcp.server 18.104.22.168 22.214.171.124
bos.net.tcp.server 126.96.36.199 188.8.131.52
bos.net.tcp.server 184.108.40.206 220.127.116.11
IBM has assigned the following APARs to this problem:
AIX Level APAR number Availability
5.3.7 IZ56311 11/11/2009
5.3.8 IZ56312 11/11/2009
5.3.9 IZ56313 11/11/2009
5.3.10 IZ56314 11/11/2009
6.1.0 IZ56315 9/23/2009
6.1.1 IZ56316 9/23/2009
6.1.2 IZ56317 9/23/2009
6.1.3 IZ56318 9/23/2009
Subscribe to the APARs here:
By subscribing, you will receive periodic email alerting you
to the status of the APAR, and a link to download the fix once
it becomes available.
Fixes are now available. The fixes can be downloaded from:
The links above are to a tar file containing this signed
advisory, fix packages, and PGP signatures for each package.
AIX Level Fix
To extract the fixes from the tar file:
tar xvf bind_fix.tar
Verify you have retrieved the fixes intact:
The checksums below were generated using the "csum -h SHA1"
(sha1sum) commands and are as follows:
csum -h SHA1 (sha1sum) filename
To verify the sums, use the text of this advisory as input to
csum or sha1sum. For example:
csum -h SHA1 -i Advisory.asc
sha1sum -c Advisory.asc
These sums should match exactly. The PGP signatures in the tar
file and on this advisory can also be used to verify the
integrity of the fixes. If the sums or signatures cannot be
confirmed, contact IBM AIX Security and describe the
discrepancy at the following address:
C. INTERIM FIX INSTALLATION
IMPORTANT: If possible, it is recommended that a mksysb backup
of the system be created. Verify it is both bootable and
readable before proceeding.
Interim fixes have had limited functional and regression
testing but not the full regression testing that takes place
for Service Packs; thus, IBM does not warrant the fully
correct functionality of an interim fix.
Interim fix management documentation can be found at:
To preview an interim fix installation:
emgr -e ipkg_name -p # where ipkg_name is the name of the
# interim fix package being previewed.
To install an interim fix package:
emgr -e ipkg_name -X # where ipkg_name is the name of the
# interim fix package being installed.
IMPORTANT: The fix will not take affect until any running BIND
servers have been stopped and restarted with the following
stopsrc -s named
startsrc -s named
There are no workarounds.
V. OBTAINING FIXES
AIX security fixes can be downloaded from:
AIX fixes can be downloaded from:
NOTE: Affected customers are urged to upgrade to the latest
applicable Technology Level and Service Pack.
VI. CONTACT INFORMATION
If you would like to receive AIX Security Advisories via email,
and click on the "My notifications" link.
To view previously issued advisories, please visit:
Comments regarding the content of this announcement can be
To obtain the PGP public key that can be used to communicate
securely with the AIX Security Team you can either:
A. Download the key from our web page:
B. Download the key from a PGP Public Key Server. The key ID is:
Please contact your local IBM AIX support center for any
eServer is a trademark of International Business Machines
Corporation. IBM, AIX and pSeries are registered trademarks of
International Business Machines Corporation. All other trademarks
are property of their respective holders.
This vulnerability was reported by Matthias Urlichs, Tom Daly, and
Internet Systems Consortium.
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