-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 IBM SECURITY ADVISORY First Issued: Thu Jan 29 11:04:38 CST 2009 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/rmsock_advisory.asc or ftp://aix.software.ibm.com/aix/efixes/security/rmsock_advisory.asc =============================================================================== VULNERABILITY SUMMARY VULNERABILITY: AIX rmsock log append file vulnerability PLATFORMS: AIX 5.2, 5.3, 6.1 SOLUTION: Apply the fix or workaround as described below. THREAT: A local attacker may append data to any file on the system. CERT VU Number: n/a CVE Number: n/a Reboot required? NO Workarounds? YES Protected by FPM? YES (high, medium, or low) Protected by SED? NO =============================================================================== DETAILED INFORMATION I. OVERVIEW The rmsock and rmsock64 commands do not create secure log files. A local attacker may exploit this error to append data to any file on the system because the command is setuid root. The following files are vulnerable: /usr/sbin/rmsock /usr/sbin/rmsock64 II. PLATFORM VULNERABILITY ASSESSMENT To determine if your system is vulnerable, execute the following command: lslpp -L bos.net.tcp.client The following fileset levels are vulnerable: AIX Fileset Lower Level Upper Level --------------------------------------------------- bos.net.tcp.client 5.2.0.0 5.2.0.112 bos.net.tcp.client 5.3.0.0 5.3.0.72 bos.net.tcp.client 5.3.7.0 5.3.7.7 bos.net.tcp.client 5.3.8.0 5.3.8.6 bos.net.tcp.client 5.3.9.0 5.3.9.2 bos.net.tcp.client 6.1.0.0 6.1.0.7 bos.net.tcp.client 6.1.1.0 6.1.1.3 bos.net.tcp.client 6.1.2.0 6.1.2.2 III. SOLUTIONS A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR number Availability ---------------------------------------------------- 5.2.0 IZ40386 Now 5.3.0 IZ42785 4/29/2009 5.3.7 IZ42786 4/29/2009 5.3.8 IZ42787 4/29/2009 5.3.9 IZ42788 4/29/2009 6.1.0 IZ41599 2/25/2009 6.1.1 IZ41593 2/25/2009 6.1.2 IZ41510 2/25/2009 Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IZ40386 http://www.ibm.com/support/docview.wss?uid=isg1IZ42785 http://www.ibm.com/support/docview.wss?uid=isg1IZ42786 http://www.ibm.com/support/docview.wss?uid=isg1IZ42787 http://www.ibm.com/support/docview.wss?uid=isg1IZ42788 http://www.ibm.com/support/docview.wss?uid=isg1IZ41599 http://www.ibm.com/support/docview.wss?uid=isg1IZ41593 http://www.ibm.com/support/docview.wss?uid=isg1IZ41510 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/rmsock_fix.tar ftp://aix.software.ibm.com/aix/efixes/security/rmsock_fix.tar The links above are 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 Technology Levels. AIX Level Fix ---------------------------------------------------- All rmsock.090129.epkg.Z To extract the fixes from the tar file: tar xvf rmsock_fix.tar cd rmsock_fix Verify you have retrieved the fixes intact: The checksums below were generated using the "sum", "cksum", "csum -h MD5" (md5sum), and "csum -h SHA1" (sha1sum) commands and are as follows: sum filename ------------------------------------ 25726 2 rmsock.090129.epkg.Z cksum filename ------------------------------------------- 3705381579 2048 rmsock.090129.epkg.Z csum -h MD5 (md5sum) filename ---------------------------------------------------------- e805476887aa51022f8e8baf51a33988 rmsock.090129.epkg.Z csum -h SHA1 (sha1sum) filename ------------------------------------------------------------------ ea6944eea6e9d7b2d1a4d198f5759e365e5ed88c rmsock.090129.epkg.Z To verify the sums, use the text of this advisory as input to csum, md5sum, or sha1sum. For example: csum -h SHA1 -i Advisory.asc md5sum -c 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. WORKAROUNDS There are two workarounds available. A. OPTION 1 Change the permissions of these commands to remove the setuid bit using the following commands: chmod 500 /usr/sbin/rmsock chmod 500 /usr/sbin/rmsock64 NOTE: chmod will disable functionality of these commands for all users except root. B. OPTION 2 (AIX 5.3 and 6.1) Use the File Permissions Manager (fpm) command to manage setuid and setgid programs. fpm documentation can be found in the AIX 6 Security Redbook at: http://www.redbooks.ibm.com/abstracts/sg247430.html An fpm level of high, medium, or low will remove the setuid bit from the affected commands. For example: fpm -l high -p # to preview changes fpm -l high # to execute changes NOTE: Please review the documentation before execution. fpm will disable functionality of multiple 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 IBM discovered and fixed this vulnerability as part of its commitment to secure the AIX operating system. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (AIX) iD8DBQFJge9nP9Qud62m600RAhVvAJ93oqGUtH/6wLiDm2AfB2wNa35HZwCdFYR9 MnSJWCrd0ohXAIs4lfRK48A= =lAvm -----END PGP SIGNATURE-----