===================================================================== CERT-Renater Note d'Information No. 2006/VULN188 _____________________________________________________________________ DATE : 21/04/2006 HARDWARE PLATFORM(S) : AIX OPERATING SYSTEM(S) : AIX ====================================================================== IBM SECURITY ADVISORY First Issued: Mon Apr 17 10:31:16 CDT 2006 ========================================================================== VULNERABILITY SUMMARY VULNERABILITY: A vulnerability in the rm_mlcache_file command allows arbitrary file overwrite. PLATFORMS: AIX 5.1, 5.2 and 5.3. SOLUTION: Apply the APAR, interim fix or workaround as described below. THREAT: A local user may overwrite arbitrary files resulting in data loss or a denial of service. CERT VU Number: n/a CVE Number: CVE-2006-1247 ========================================================================= DETAILED INFORMATION I. Description =============== A vulnerability was discovered in the rm_mlcache_file command that allows a a local user to overwrite arbitrary files. rm_mlcache_file ships as part of the bos.rte.install fileset. II. Impact ========== A local user may overwrite arbitrary files. This may result in data loss or a denial of service. III. Solutions =============== A. Official Fix IBM provides the following fixes: APAR number for AIX 5.1.0: IY82866 (available approx. 07/19/06) APAR number for AIX 5.2.0: IY82285 (available approx. 04/26/06) APAR number for AIX 5.3.0: IY82357 (available) NOTE: Affected customers are urged to upgrade to the latest applicable Technology Level. B. Interim Fix Interim fixes are available. The ifixes can be downloaded via ftp from: ftp://aix.software.ibm.com/aix/efixes/security/rm_mlcache_file_ifix.tar.Z rm_mlcache_file_ifix.tar.Z is a compressed tarball containing this advisory, ifix packages and cleartext PGP signatures for each ifix package. Verify you have retrieved the fixes intact: +------------------------------------------ The interim fixes below are named by using the APAR corresponding to the release that the fix applies to. The APAR is followed by an underscore and the Technology Level for the particular AIX release that a fix applies to. The checksums below were generated using the "sum" and "md5sum" commands and are as follows: Filename sum md5 ======================================================================== IY82866_09.060412.epkg.Z 40955 9 4242b3797bfc5422af0f7f2b54fbf302 IY82285_06.060410.epkg.Z 06704 9 9a14ab7d8f8373b4c93c2c46e0ddf83a IY82285_07.060410.epkg.Z 03559 9 88c965e583b89d7f5f18c3d73963d223 IY82285_08.060410.epkg.Z 17761 9 0e1206b9efda47e000a0c98abd055636 IY82357_02.060410.epkg.Z 36914 9 792f06e925d2fa126a71f02c73b63702 IY82357_03.060410.epkg.Z 28447 9 a55865da31f7635c76ce6b39ab2e57a6 These sums should match exactly. The PGP signatures in the compressed tarball and on this advisory can also be used to verify the integrity of the various files they correspond to. If the sums or signatures cannot be confirmed, double check the command results and the download site address. If those are OK, contact IBM AIX Security at security-alert@austin.ibm.com and describe the discrepancy. The following table shows the prerequisite lower and upper fileset levels for the fixes above. These levels are inclusive and apply to bos.rte.install. Technology Filename Lower Level Upper Level Level =================================================================== 5100-09 IY82866_09.060410.epkg.Z 5.1.0.66 5.1.0.67 5200-06 IY82285_06.060410.epkg.Z 5.2.0.60 5.2.0.74 5200-07 IY82285_07.060410.epkg.Z 5.2.0.75 5.2.0.84 5200-08 IY82285_08.060410.epkg.Z 5.2.0.85 5.2.0.94 5300-02 IY82357_02.060410.epkg.Z 5.3.0.20 5.3.0.29 5300-03 IY82357_03.060410.epkg.Z 5.3.0.30 5.3.0.39 IMPORTANT: If possible, it is recommended that a mksysb backup of the system is created. Verify it is both bootable, and readable before proceeding. These ifixes have not been fully regression tested; thus, IBM does not warrant the fully correct functioning of the ifix. Customers install the ifix and operate the modified version of AIX at their own risk. Interim Installation Instructions: +--------------------------------- These packages use the new Interim Fix Management Solution to install and manage ifixes. More information can be found at: http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html To preview an epkg ifix installation execute the following command: # emgr -e ipkg_name -p # where ipkg_name is the name of the # ifix package being previewed. To install an epkg ifix package, execute the following command: # emgr -e ipkg_name -X # where ipkg_name is the name of the # ifix package being installed. The "X" flag will expand any filesystems if required. C. Workaround Make rm_mlcache_file executable only by the root user +---------------------------------------------------- To make rm_mlcache_file executable only by root, run the following command: # chmod 500 /usr/bin/rm_mlcache_file Verify the that the file mode bits have been updated: # ls -la rm_mlcache_file - - -r-x------ 1 root system 12758 Feb 15 10:25 rm_mlcache_file Note that only the root user will be able to use the rm_mlcache_file command. Since this command is invoked by the oslevel script, only root will be able to use oslevel. IV. Obtaining Fixes =================== AIX Version 5 APARs can be downloaded from: http://www.ibm.com/servers/eserver/support/unixservers/aixfixes.html Security related Interim Fixes can be downloaded from: ftp://aix.software.ibm.com/aix/efixes/security V. Contact Information ======================= If you would like to receive AIX Security Advisories via email, 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 request the PGP public key that can be used to communicate securely with the AIX Security Team send email to security-alert@austin.ibm.com with a subject of "get key". The key can also be downloaded from a PGP Public Key Server. The key id is 0x9391C1F2. 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. ====================================================================== ========================================================= Les serveurs de référence du CERT-Renater http://www.urec.fr/securite http://www.cru.fr/securite http://www.renater.fr ========================================================= + CERT-RENATER | tel : 01-53-94-20-44 + + 151 bd de l'Hopital | fax : 01-53-94-20-41 + + 75013 Paris | email: certsvp@renater.fr + =========================================================