02 October 2009
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2009.1356.2 AIX NFSv4 nfs_portmon and Kerberos vulnerabilities 2 October 2009 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: NFSv4 Kerberos Publisher: IBM Operating System: AIX Impact/Access: Unauthorised Access -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2009-3517 CVE-2009-3516 Revision History: October 2 2009: Added CVE References September 30 2009: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 IBM SECURITY ADVISORY First Issued: Tue Sep 29 12:42:51 CDT 2009 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/nfs4_advisory.asc or ftp://aix.software.ibm.com/aix/efixes/security/nfs4_advisory.asc VULNERABILITY SUMMARY VULNERABILITY: AIX NFSv4 nfs_portmon and Kerberos vulnerabilities. PLATFORMS: AIX 5.3, 6.1 SOLUTION: Apply the fix as described below. THREAT: A local user can gain unauthorized access to Kerberized AIX NFSv4 shares. A remote user can gain unauthorized network access to AIX NFSv4 shares protected by the nfs_portmon tunable. CERT VU Number: n/a CVE Number: n/a Reboot required? YES* Workarounds? NO Protected by FPM? NO Protected by SED? NO * For the nfs_portmon fix, the machine must be rebooted to reload the NFS kernel extensions. For the Kerberos fix, the gssd daemon must be restarted. DETAILED INFORMATION I. DESCRIPTION There are two security vulnerabilities in the AIX NFSv4 (Network File System version 4) implementation. The first vulnerability is an error in the handling of the NFSv4 Kerberos credential cache. The successful exploitation of this vulnerability allows a local user to access Kerberized network shares without authorization. The second vulnerability is that the nfs_portmon tunable is not utilized correctly in NFSv4. The successful exploitation of this vulnerability allows a remote user to access network shares protected by nfs_portmon without authorization. The following commands are vulnerable: /usr/sbin/gssd /usr/lib/drivers/nfs.ext II. PLATFORM VULNERABILITY ASSESSMENT To determine if your system is vulnerable, execute the following command: lslpp -L bos.net.nfs.client The following fileset levels are vulnerable: AIX Fileset Lower Level Upper Level --------------------------------------------------- bos.net.nfs.client all earlier versions of 5.3 bos.net.nfs.client 188.8.131.52 184.108.40.206 bos.net.nfs.client 220.127.116.11 18.104.22.168 bos.net.nfs.client 22.214.171.124 126.96.36.199 bos.net.nfs.client 188.8.131.52 184.108.40.206 bos.net.nfs.client 220.127.116.11 18.104.22.168 bos.net.nfs.client 22.214.171.124 126.96.36.199 III. SOLUTIONS A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR number Availability ---------------------------------------------------- 5.3.7 IZ50496 Now (SP9) 5.3.8 IZ50444 Now (SP7) 5.3.9 IZ50399 Now (SP4) 6.1.0 IZ49278 Now (SP9) 6.1.1 IZ49096 Now (SP5) 6.1.2 IZ49024 Now (SP4) Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IZ50496 http://www.ibm.com/support/docview.wss?uid=isg1IZ50444 http://www.ibm.com/support/docview.wss?uid=isg1IZ50399 http://www.ibm.com/support/docview.wss?uid=isg1IZ49278 http://www.ibm.com/support/docview.wss?uid=isg1IZ49096 http://www.ibm.com/support/docview.wss?uid=isg1IZ49024 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/nfs4_fix.tar ftp://aix.software.ibm.com/aix/efixes/security/nfs4_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 ---------------------------------------------------- 5.3.7 bos.net.nfs.client.188.8.131.52.U 5.3.8 bos.net.nfs.client.184.108.40.206.U 5.3.9 bos.net.nfs.client.220.127.116.11.U 6.1.0 bos.net.nfs.client.18.104.22.168.U 6.1.1 bos.net.nfs.client.22.214.171.124.U 6.1.2 bos.net.nfs.client.126.96.36.199.U To extract the fixes from the tar file: tar xvf nfs4_fix.tar cd nfs4_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 ---------------------------------------------------------------------- 6498591e2a75f5081f30487220ef205649be34a3 bos.net.nfs.client.188.8.131.52.U 55ff5576fccb052c05d0432250619ef9e3bd1fe1 bos.net.nfs.client.184.108.40.206.U c98585939e0bf02c5b88adbb0bbc48c52d261e07 bos.net.nfs.client.220.127.116.11.U d0d3f99ea11fcae97bacd782b904363f60191351 bos.net.nfs.client.18.104.22.168.U 5c73c73eca95fa782f82ade9c5b56f64217113ab bos.net.nfs.client.22.214.171.124.U a3251008ee0e4e4a67b7e9beff5a0d9550407fcf bos.net.nfs.client.126.96.36.199.U 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: email@example.com C. 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. IV. WORKAROUNDS There are no workarounds. 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: firstname.lastname@example.org 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 The vulnerabilties were reported by Anton Lundin. - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (AIX) iD8DBQFKwkdYP9Qud62m600RAjxsAJwNxkpMReX6iAv222wuUJLULzEJwQCeLahd SFVrhFko9oMabu83JeAiYL8= =Dz6F - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. 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On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iD8DBQFKxVs7NVH5XJJInbgRAuHIAJ4jLTsOGGgu/H8VU+rcnhFgtvvNcwCfbxUZ nNZQt6DfVxVXmY9WEMq+K74= =wuMJ -----END PGP SIGNATURE-----