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AUSCERT External Security Bulletin Redistribution
AIX NFSv4 nfs_portmon and Kerberos vulnerabilities
2 October 2009
AusCERT Security Bulletin Summary
Operating System: AIX
Impact/Access: Unauthorised Access -- Remote/Unauthenticated
CVE Names: CVE-2009-3517 CVE-2009-3516
Revision History: October 2 2009: Added CVE References
September 30 2009: Initial Release
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IBM SECURITY ADVISORY
First Issued: Tue Sep 29 12:42:51 CDT 2009
The most recent version of this document is available here:
VULNERABILITY: AIX NFSv4 nfs_portmon and Kerberos vulnerabilities.
PLATFORMS: AIX 5.3, 6.1
SOLUTION: Apply the fix as described below.
THREAT: A local user can gain unauthorized access to
Kerberized AIX NFSv4 shares. A remote user can gain
unauthorized network access to AIX NFSv4 shares
protected by the nfs_portmon tunable.
CERT VU Number: n/a
CVE Number: n/a
Reboot required? YES*
Protected by FPM? NO
Protected by SED? NO
* For the nfs_portmon fix, the machine must be rebooted to reload the
NFS kernel extensions. For the Kerberos fix, the gssd daemon must
There are two security vulnerabilities in the AIX NFSv4 (Network
File System version 4) implementation.
The first vulnerability is an error in the handling of the NFSv4
Kerberos credential cache. The successful exploitation of this
vulnerability allows a local user to access Kerberized network
shares without authorization.
The second vulnerability is that the nfs_portmon tunable is not
utilized correctly in NFSv4. The successful exploitation of this
vulnerability allows a remote user to access network shares
protected by nfs_portmon without authorization.
The following commands are vulnerable:
II. PLATFORM VULNERABILITY ASSESSMENT
To determine if your system is vulnerable, execute the following
lslpp -L bos.net.nfs.client
The following fileset levels are vulnerable:
AIX Fileset Lower Level Upper Level
bos.net.nfs.client all earlier versions of 5.3
bos.net.nfs.client 22.214.171.124 126.96.36.199
bos.net.nfs.client 188.8.131.52 184.108.40.206
bos.net.nfs.client 220.127.116.11 18.104.22.168
bos.net.nfs.client 22.214.171.124 126.96.36.199
bos.net.nfs.client 188.8.131.52 184.108.40.206
bos.net.nfs.client 220.127.116.11 18.104.22.168
IBM has assigned the following APARs to this problem:
AIX Level APAR number Availability
5.3.7 IZ50496 Now (SP9)
5.3.8 IZ50444 Now (SP7)
5.3.9 IZ50399 Now (SP4)
6.1.0 IZ49278 Now (SP9)
6.1.1 IZ49096 Now (SP5)
6.1.2 IZ49024 Now (SP4)
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 nfs4_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. 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.
To preview a fix installation:
installp -a -d fix_name -p all # where fix_name is the name of the
# fix package being previewed.
To install a fix package:
installp -a -d fix_name -X all # where fix_name is the name of the
# fix package being installed.
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.
The vulnerabilties were reported by Anton Lundin.
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