-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 IBM SECURITY ADVISORY First Issued: Tue Feb 10 12:08:53 CST 2009 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/at_advisory.asc or ftp://aix.software.ibm.com/aix/efixes/security/at_advisory.asc VULNERABILITY SUMMARY VULNERABILITY: AIX at information disclosure vulnerability PLATFORMS: AIX 5.2, 5.3, 6.1 SOLUTION: Apply the fix or workaround as described below. THREAT: A local attacker may read any file on the system. CERT VU Number: n/a CVE Number: n/a Reboot required? NO Workarounds? YES Protected by FPM? NO Protected by SED? NO DETAILED INFORMATION I. OVERVIEW The at command does not drop permissions when reading certain files. A local attacker may exploit this error to read any file on the system because the command is setuid root. The following file is vulnerable: /usr/bin/at II. PLATFORM VULNERABILITY ASSESSMENT To determine if your system is vulnerable, execute the following command: lslpp -L bos.rte.cron The following fileset levels are currently vulnerable: AIX Fileset Lower Level Upper Level --------------------------------------------------- bos.rte.cron 5.2.0.0 5.2.0.106 bos.rte.cron 5.3.0.0 5.3.0.63 bos.rte.cron 5.3.7.0 5.3.7.1 bos.rte.cron 5.3.8.0 5.3.8.1 bos.rte.cron 5.3.9.0 5.3.9.0 bos.rte.cron 6.1.0.0 6.1.0.1 bos.rte.cron 6.1.1.0 6.1.1.2 bos.rte.cron 6.1.2.0 6.1.2.0 III. SOLUTIONS A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR number Availability ---------------------------------------------------- 5.2.0 IZ43452 7/22/2009 5.3.0 IZ43453 4/29/2009 5.3.7 IZ43454 4/29/2009 5.3.8 IZ43455 4/29/2009 5.3.9 IZ43456 4/29/2009 6.1.0 IZ43457 6/03/2009 6.1.1 IZ43458 6/03/2009 6.1.2 IZ43459 6/03/2009 Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IZ43452 http://www.ibm.com/support/docview.wss?uid=isg1IZ43453 http://www.ibm.com/support/docview.wss?uid=isg1IZ43454 http://www.ibm.com/support/docview.wss?uid=isg1IZ43455 http://www.ibm.com/support/docview.wss?uid=isg1IZ43456 http://www.ibm.com/support/docview.wss?uid=isg1IZ43457 http://www.ibm.com/support/docview.wss?uid=isg1IZ43458 http://www.ibm.com/support/docview.wss?uid=isg1IZ43459 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 now available. The fixes can be downloaded from: http://aix.software.ibm.com/aix/efixes/security/at_fix.tar ftp://aix.software.ibm.com/aix/efixes/security/at_fix.tar The links above are to a tar file containing this signed advisory, fix packages, and PGP signatures for each package. AIX Level Fix ---------------------------------------------------- 5.2.0 TL10 IZ43452_10.090206.epkg.Z 5.3.0 TL6 IZ43453_06.090206.epkg.Z 5.3.7 IZ43454_07.090206.epkg.Z 5.3.8 IZ43455_08.090206.epkg.Z 5.3.9 IZ43456_09.090206.epkg.Z 6.1.0 IZ43457_00.090206.epkg.Z 6.1.1 IZ43458_01.090206.epkg.Z 6.1.2 IZ43459_02.090206.epkg.Z To extract the fixes from the tar file: tar xvf at_fix.tar cd at_fix Verify you have retrieved the fixes intact: The checksums below were generated using the "csum -h SHA1" (sha1sum) commands and are as follows: csum -h SHA1 (sha1sum) filename ------------------------------------------------------------------ 5027642b26eb5c336e2a935780afead9fa2a50bc IZ43452_10.090206.epkg.Z e2034961fe8902ceb68a38382861bd9e911aa2d5 IZ43453_06.090206.epkg.Z ff59e96307b014ff999313c42093599edd4908db IZ43454_07.090206.epkg.Z 1b536c647f57da7e8d2d520339c9db7fb8fe41be IZ43455_08.090206.epkg.Z 7d84846c200e5e257fcdcd27f9e928d06e213a3b IZ43456_09.090206.epkg.Z 649a4e775898d1d955fd03c1b05fef17b3a3f420 IZ43457_00.090206.epkg.Z 47b91524b68b15e1421aad3c07d8e70d9c1ae498 IZ43458_01.090206.epkg.Z 881b95a2eb1a8529abf4d1d133efd055898886b7 IZ43459_02.090206.epkg.Z To verify the sums, use the text of this advisory as input to csum or 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 and describe the discrepancy at the following address: security-alert@austin.ibm.com C. 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. 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. WORKAROUND Change the permissions of these commands to remove the setuid bit using the following commands: chmod 500 /usr/bin/at NOTE: chmod will disable functionality of these commands for all users except root. V. OBTAINING FIXES AIX security fixes can be downloaded from: http://aix.software.ibm.com/aix/efixes/security or ftp://aix.software.ibm.com/aix/efixes/security AIX fixes can be downloaded from: http://www.ibm.com/eserver/support/fixes/fixcentral/main/pseries/aix NOTE: Affected customers are urged to upgrade to the latest applicable Technology Level and Service Pack. 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. Download the key from our web page: http://www.ibm.com/systems/resources/systems_p_os_aix_security_pgpkey.txt B. Download the key from a PGP Public Key Server. The key ID is: 0xADA6EB4D 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 This vulnerability was reported by iDefense Labs. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (AIX) iD8DBQFJkc2YP9Qud62m600RAoBgAKCtA57mm2MmZ8havDsbb40wwPJmcACgv8aW N05oJmQtlL5GPGFSu/WCtV8= =UPjo -----END PGP SIGNATURE-----