IBM SECURITY ADVISORY First Issued: Wed Dec 14 17:01:02 CST 2011 | Updated: Thu Dec 12 12:55:11 CST 2013 | Update: 1. Added KEYs for parsing purposes | 2. Moved to OpenSSL signature The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/xorg_advisory.asc ftp://aix.software.ibm.com/aix/efixes/security/xorg_advisory.asc =============================================================================== VULNERABILITY SUMMARY 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 CVSS=? CVE-2007-6429 CVSS=? Reboot required? NO Workarounds? NO Protected by FPM? NO Protected by SED? NO =============================================================================== DETAILED INFORMATION I. DESCRIPTION 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 KEY ----------------------------------------------------------- X11.base.rte 6.1.4.0 6.1.4.3 key_w_fs X11.base.rte 6.1.5.0 6.1.5.1 key_w_fs X11.base.rte 6.1.6.0 6.1.6.16 key_w_fs X11.base.rte 6.1.7.0 6.1.7.0 key_w_fs X11.base.rte 7.1.0.0 7.1.0.15 key_w_fs X11.base.rte 7.1.1.0 7.1.1.0 key_w_fs III. SOLUTIONS A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR number Availability KEY ---------------------------------------------------------------- 6.1.5 IV07021 TBD sp8 key_w_apar 6.1.6 IV07022 TBD sp7 key_w_apar 6.1.7 IV08676 Available sp2 key_w_apar 7.1.0 TBD TBD sp5 key_w_apar 7.1.1 IV08786 Available sp2 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IV07021 http://www.ibm.com/support/docview.wss?uid=isg1IV07022 http://www.ibm.com/support/docview.wss?uid=isg1IV08676 http://www.ibm.com/support/docview.wss?uid=isg1IV08786 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/xorg_ifix.tar The link above is to a tar file containing this signed advisory, fix packages, and OpenSSL 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) KEY ----------------------------------------------------------------- 6.1.5 20867.610.111201.epkg.Z key_w_fix 6.1.6 20867.610.111201.epkg.Z key_w_fix 6.1.7 20867.610.111201.epkg.Z key_w_fix 7.1.0 20867.710.111201.epkg.Z key_w_fix 7.1.1 20867.710.111201.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf xorg_ifix.tar cd xorg_ifix 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 ------------------------------------------------------------------ e98f5a797ebb4940f519c19c01d95a3b80913ec4 20867.610.111201.epkg.Z 41ee279f6a522e2ff6b01e6888b6d20fe892f467 20867.710.111201.epkg.Z 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 OpenSSL 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. openssl dgst -sha1 -verify AIX_PSIRT_pub.asc -signature file.asc.sig file.asc 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: 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. IV. WORKAROUNDS No workarounds V. 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 OpenSSL public key that can be used to verify the signed advisories and ifixes: Download the key from our web page: http://www.ibm.com/systems/resources/systems_p_os_aix_security_pubkey.txt 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: security-alert@austin.ibm.com B. 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. VI. REFERENCES: Note: Keywords labeled as KEY in this document are used for parsing purposes. http://lists.freedesktop.org/archives/xorg-announce/2008-January/000441.html CVE-2007-6427: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-6427 CVE-2007-6429: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-6429