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AUSCERT External Security Bulletin Redistribution
Multiple vulnerabilities in the X server
16 December 2011
AusCERT Security Bulletin Summary
Product: AIX 7.1
Operating System: AIX
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Denial of Service -- Remote/Unauthenticated
CVE Names: CVE-2007-6429 CVE-2007-6427
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IBM SECURITY ADVISORY
First Issued: Wed Dec 14 17:01:02 CST 2011
The most recent version of this document is available here:
VULNERABILITY: Multiple vulnerabilities in the X server
PLATFORMS: AIX 6.1 and 7.1
SOLUTION: Apply the fix described below.
THREAT: See below.
CVE Number: CVE-2007-6427
Reboot required? NO
Protected by FPM? NO
Protected by SED? NO
CVE-2007-6427 - Xinput extension memory corruption
The vulnerable code exists in multiple functions in the XInput
extension, and occurs when swapping the byte order of client requests.
By claiming to be sending integer data in the opposite byte order of
the server, the client can cause the server to swap the byte order of a
request. The number of bytes swapped can be controlled by the client,
and is not properly validated by the server. This results in the
corruption of heap memory located after the client's request data.
CVE-2007-6429 - MIT-SHM and EVI extensions integer overflows
The MIT-SHM extension vulnerability exists in the code responsible
for creating a pixmap in shared memory. When allocating the pixmap,
the server uses values from the request to verify that the requested
size is not greater than the allocated shared memory. The calculation
can overflow, which leads to the overwriting of arbitrary addresses in
memory that aren't part of the shared memory segment.
The EVI extension vulnerability exists in the code responsible for
processing the GetVisualInfo request. When processing this request,
the server uses a 32-bit value provided by the client in an arithmetic
operation that calculates the number of bytes to allocate for a
dynamic buffer. This operation can overflow, which later leads to the
buffer being overflowed.
II. PLATFORM VULNERABILITY ASSESSMENT
To determine if your system is vulnerable, run the following command:
# lslpp -l | grep X11.base.rte
The following filesets are vulnerable:
AIX Fileset Lower Level Upper Level
X11.base.rte 188.8.131.52 184.108.40.206
X11.base.rte 220.127.116.11 18.104.22.168
X11.base.rte 22.214.171.124 126.96.36.199
X11.base.rte 188.8.131.52 184.108.40.206
X11.base.rte 220.127.116.11 18.104.22.168
X11.base.rte 22.214.171.124 126.96.36.199
IBM has assigned the following APARs to this problem:
AIX Level APAR number Availability
6.1.5 IV07021 sp8 TBD
6.1.6 IV07022 sp7 TBD
6.1.7 IV08676 sp2 available
7.1.0 TBD sp5 TBD
7.1.1 IV08786 sp2 available
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 available. The fixes can be downloaded via ftp
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
AIX Level Interim Fix (*.Z)
To extract the fixes from the tar file:
tar xvf xorg_ifix.tar
Verify you have retrieved the fixes intact:
The checksums below were generated using the
csum -h SHA1" (sha1sum) command
and are as follows:
csum -h SHA1 (sha1sum) filename
To verify the sums, use the text of this advisory as input to
csum. For example:
csum -h SHA1 -i xorg_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
email@example.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; 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.
V. 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 request 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:
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.
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