FLASH: AIX NFSv4 vulnerability

 

VULNERABILITY: AIX NFSv4 vulnerability

PLATFORMS: AIX 5.3, 6.1, and 7.1 releases

SOLUTION: Apply the fix as described below.

THREAT: See below

CVE Numbers: CVE-2012-4817

Reboot required? YES
Workarounds? NO
Protected by FPM? NO
Protected by SED? NO

===============================================================================
DETAILED INFORMATION

I. DESCRIPTION ( From cve.mitre.org)

GID in NFSv4 is loosely enforced.

II. CVSS

CVSS Base Score: 5
CVSS Temporal Score: See http://xforce.iss.net/xforce/xfdb/78431 for the
current score
CVSS Environmental Score*: Undefined
CVSS String: (AV:N/AC:L/Au:N/C:N/I:N/A:P)

III. PLATFORM VULNERABILITY ASSESSMENT

Note: To use the following commands on VIOS you must first
execute:

oem_setup_env

To determine if your system is vulnerable, execute the following
command:

lslpp -L bos.net.nfs.client

The following fileset levels are vulnerable:

AIX Fileset Lower Level Upper Level
——————————————————————
bos.net.nfs.client 5.3.12.0 5.3.12.5
bos.net.nfs.client 6.1.6.0 6.1.6.17
bos.net.nfs.client 6.1.7.0 6.1.7.2
bos.net.nfs.client 7.1.0.0 7.1.0.20
bos.net.nfs.client 7.1.1.0 7.1.1.3

IV. SOLUTIONS

A. APARS

IBM has assigned the following APARs to this problem:

AIX Level APAR number Availability
—————————————————
5.3.12 IV17855 Available as of SP6
6.1.6 IV10327 Available as of SP7
6.1.7 IV11629 Available as of SP3
7.1.0 IV26436 12/12/12 sp8
7.1.1 IV12169 Available as of SP4

Subscribe to the APARs here:

http://www.ibm.com/support/docview.wss?uid=isg1IV17855
http://www.ibm.com/support/docview.wss?uid=isg1IV10327
http://www.ibm.com/support/docview.wss?uid=isg1IV11629
http://www.ibm.com/support/docview.wss?uid=isg1IV26436
http://www.ibm.com/support/docview.wss?uid=isg1IV12169

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.

B. FIXES

Fixes are available. The fixes can be downloaded via ftp
from:

ftp://aix.software.ibm.com/aix/efixes/security/nfsv4_fix1.tar

The link above is to a tar file containing this signed
advisory, fix packages, and PGP signatures for each package.
The fixes below include prerequisite checking. This will
enforce the correct mapping between the fixes and AIX
Technology Levels.

AIX Level Interim Fix (*.Z)
——————————————————————-
7.1.0.7 IV26436s07.120907.epkg.Z

VIOS Level Interim Fix (*.Z)
——————————————————————-
2.2.1.4-FP-25 SP-02 Included in current SP

To extract the fixes from the tar file:

tar xvf nfsv4_fix1.tar
cd nfsv4_fix1

Verify you have retrieved the fixes intact:

The checksums below were generated using the
“csum -h SHA1” (sha1sum) command is the followng:

csum -h SHA1 (sha1sum) filename
——————————————————————
8f42e3c1a5eb3a0d73d7be8d38265544f9abd866 IV26436s07.120907.epkg.Z

To verify the sum, use the text of this advisory as input to 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 at
security-alert@austin.ibm.com and describe the discrepancy.

C. FIX AND 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.

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.

Interim fixes have had limited functional and regression
testing but not the full regression testing that takes place
for Service Packs; however, IBM does fully support them.

Interim fix management documentation can be found at:

http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html

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.

V. WORKAROUNDS

There are no workarounds.

VI. CONTACT INFORMATION

If you would like to receive AIX Security Advisories via email,
please visit:

http://www.ibm.com/systems/support

and click on the “My notifications” link.

To view previously issued advisories, please visit:

http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd

Comments regarding the content of this announcement can be
directed to:

security-alert@austin.ibm.com

To obtain the PGP public key that can be used to communicate
securely with the AIX Security Team you can either:

A. Send an email with “get key” in the subject line to:

security-alert@austin.ibm.com

B. Download the key from our web page:

http://www.ibm.com/systems/resources/systems_p_os_aix_security_pgpkey.txt

C. Download the key from a PGP Public Key Server. The key ID is:

0x28BFAA12

Please contact your local IBM AIX support center for any
assistance.

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.

VII. ACKNOWLEDGMENTS

IBM discovered and fixed this vulnerability as part of its
commitment to secure the AIX operating system.

VIII. REFERENCES:

Complete CVSS Guide: http://www.first.org/cvss/cvss-guide.html
On-line Calculator V2:
http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2
X-Force Vulnerability Database: http://xforce.iss.net/xforce/xfdb/78431
CVE-2012-4817: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-4817

*The CVSS Environment Score is customer environment specific and will
ultimately impact the Overall CVSS Score. Customers can evaluate the
impact of this vulnerability in their environments by accessing the links
in the Reference section of this Flash.

Note: According to the Forum of Incident Response and Security Teams
(FIRST), the Common Vulnerability Scoring System (CVSS) is an “industry
open standard designed to convey vulnerability severity and help to
determine urgency and priority of response.” IBM PROVIDES THE CVSS SCORES
“AS IS” WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE
RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY
VULNERABILITY.

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