===================================================================== CERT-Renater Note d'Information No. 2007/VULN323 _____________________________________________________________________ DATE : 27/07/2007 HARDWARE PLATFORM(S) : / OPERATING SYSTEM(S) : AIX 5.2, AIX 5.3 running arp command. ====================================================================== IBM SECURITY ADVISORY First Issued: Tue Jul 24 14:07:25 CDT 2007 =============================================================================== VULNERABILITY SUMMARY VULNERABILITY: AIX arp Buffer Overflow Vulnerability PLATFORMS: AIX 5.2, 5.3 SOLUTION: Apply the APAR, interim fix or workaround as described below. THREAT: An attacker may run arbitrary code with root privileges. CERT VU Number: n/a CVE Number: n/a =============================================================================== DETAILED INFORMATION I. OVERVIEW The arp command displays and modifies the Internet-to-adapter address translation tables used by the Address in Networks and communication management. This program is installed as setuid with the devices.common.IBM.atm.rte fileset. NOTE: IBM has removed support for ATM functionality. This advisory is only to notify users that their system is vulnerable and to provide a patch for releases which are still delivering the fileset for legacy purposes. II. DESCRIPTION A buffer overflow vulnerability exits within the setuid program arp. This advisory specifically addresses the atm subset of the arp command. III. IMPACT A successful exploitation of this buffer overflow will allow an unprivileged user to execute arbitrary code with root privileges. IV. PLATFORM VULNERABILITY ASSESSMENT To determine if your system is vulnerable, run the following command: # lslpp -l | grep devices.common.IBM.atm.rte The following filesets are vulnerable: AIX Level Lower Level Upper Level ------------------------------------------------- 5.2.0 5.2.0.51 5.2.0.95 5.3.0 5.3.0.40 5.3.0.60 V. SOLUTIONS A. APARS IBM provides the following fixes: AIX Level APAR number Availability -------------------------------------------------------------------- 5.2.0 IZ00521 10/31/2007 (subject to change) 5.3.0 IZ00510 08/08/2007 (subject to change) AIX Version 5 APARs can be downloaded from: http://www.ibm.com/servers/eserver/support/unixservers/aixfixes.html NOTE: Affected customers are urged to upgrade to the latest applicable Technology Level and Service Pack. B. INTERIM FIXES Interim fixes are available. The interim fix can be downloaded via ftp from: ftp://aix.software.ibm.com/aix/efixes/security/atm_ifix.tar.Z This is a compressed tarball containing this advisory, interim fix packages and PGP signatures for each package. The interim fixes below include prerequisite checking. This will enforce the correct mapping between the fixes and AIX Technology Levels. AIX Release & Technology Level Interim fix --------------------------------------------------------------- 5200-08 IZ00521_08.070622.epkg.Z 5200-09 IZ00521_09.070622.epkg.Z 5200-10 IZ00521_10.070622.epkg.Z 5300-04 IZ00510_04.070622.epkg.Z 5300-05 IZ00510_05.070622.epkg.Z 5300-06 IZ00510_06.070622.epkg.Z IMPORTANT: If possible, it is recommended that a mksysb backup of the system be created. Verify it is both bootable and readable before proceeding. These interim fixes have not been fully regression tested; thus, IBM does not warrant the fully correct functionality of the interim fix. Customers install the interim fix and operate the modified version of AIX at their own risk. Verify you have retrieved the fixes intact: The interim fixes below are named by using the technology level corresponding to the release that the fix applies to. The checksums below were generated using the "sum" and "md5sum" commands and are as follows: Filename sum md5sum ---------------------------------------------------------------------- IZ00521_08.070622.epkg.Z 19355 11 888d9ff0634cd3833c7b84adda724ef2 IZ00521_09.070622.epkg.Z 22872 11 327f32bb81b4f7e03131ce2cc4fa25ce IZ00521_10.070622.epkg.Z 26138 11 636584044285fda77d308194b7988b7c IZ00510_04.070622.epkg.Z 15081 11 96e94ffc7ff68bacdc5d624cd6ddf7fe IZ00510_05.070622.epkg.Z 57550 11 db98e7b8f3c212857f89e9252d74967d IZ00510_06.070622.epkg.Z 46918 11 e490d017608db8e83c9a04d56f25b348 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. C. INTERIM FIX INSTALLATION These packages use the new Interim Fix Management Solution to install and manage interim fixes. More information can be found at: http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html To preview an epkg interim fix installation execute the following command: # emgr -e ipkg_name -p # where ipkg_name is the name of the # interim fix package being previewed. To install an epkg interim fix package, execute the following command: # emgr -e ipkg_name -X # where ipkg_name is the name of the # interim fix package being installed. The "X" flag will expand any filesystems if required. VI. WORKAROUNDS If the atm functionality is not needed on your platform, the best solution is to remove the fileset listed above. VII. 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 VII. 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 0x4265D862. 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. VIII. ACKNOWLEDGMENTS This vulnerability was discovered internal to IBM as part of its commitment to secure the AIX operating system. ====================================================================== ========================================================= 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 + =========================================================