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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2010.0220 AIX xntpd denial-of-service vulnerability 4 March 2010 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: xntpd Publisher: IBM Operating System: AIX Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2009-3563 Reference: ESB-2009.1613 Original Bulletin: http://aix.software.ibm.com/aix/efixes/security/xntpd_advisory.as - --------------------------BEGIN INCLUDED TEXT-------------------- IBM SECURITY ADVISORY First Issued: Tue Mar 2 09:31:41 CST 2010 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/xntpd_advisory.asc VULNERABILITY SUMMARY VULNERABILITY: AIX xntpd denial-of-service vulnerability PLATFORMS: AIX 5.3, 6.1, and earlier releases SOLUTION: Apply the fix or workaround as described below. THREAT: A remote, unauthenticated attacker may be able to cause a denial-of-service condition on a vulnerable NTP server. CERT VU Number: 568372 CVE Number: CVE-2009-3563 Reboot required? NO Workarounds? YES Protected by FPM? NO Protected by SED? NO DETAILED INFORMATION I. DESCRIPTION (from US-CERT) "NTP mode 7 (MODE_PRIVATE) is used by the ntpdc query and control utility. In contrast, ntpq uses NTP mode 6 (MODE_CONTROL), while routine NTP time transfers use modes 1 through 5. Upon receipt of an incorrect mode 7 request or a mode 7 error response from an address that is not listed in a "restrict ... noquery" or "restrict ... ignore" segment, ntpd will reply with a mode 7 error response and log a message." "If an attacker spoofs the source address of ntpd host A in a mode 7 response packet sent to ntpd host B, both A and B will continuously send each other error responses, for as long as those packets get through." "If an attacker spoofs an address of ntpd host A in a mode 7 response packet sent to ntpd host A, then host A will respond to itself endlessly, consuming CPU and logging excessively." Please see the following for more information: http://www.kb.cert.org/vuls/id/568372 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3563 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 ------------------------------------------------ all earlier levels are vulnerable bos.net.tcp.client 5.3.08.0 5.3.08.10 bos.net.tcp.client 6.1.04.0 6.1.04.03 bos.net.tcp.client 5.3.09.0 5.3.09.06 bos.net.tcp.client 5.3.10.0 5.3.10.01 bos.net.tcp.client 5.3.11.0 5.3.11.01 bos.net.tcp.client 6.1.01.0 6.1.01.07 bos.net.tcp.client 6.1.02.0 6.1.02.06 bos.net.tcp.client 6.1.03.0 6.1.03.03 III. SOLUTION A. FIXES Fixes are now available. The fixes can be downloaded from: http://aix.software.ibm.com/aix/efixes/security/xntpd_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 ------------------------------------------------------------------- 5.3.8 IZ68659_08.100302.epkg.Z 5.3.9 IZ71093_09.100302.epkg.Z 5.3.10 IZ71608_10.100302.epkg.Z 5.3.11 IZ71610_11.100302.epkg.Z 6.1.1 IZ71611_01.100302.epkg.Z 6.1.2 IZ71613_02.100302.epkg.Z 6.1.3 IZ71614_03.100302.epkg.Z 6.1.4 IZ71071_04.100302.epkg.Z To extract the fixes from the tar file: tar xvf xntpd_fix.tar cd xntpd_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 ------------------------------------------------------------------ db28b4651bfeea9a5a293dfb585206ba3f67b30c IZ68659_08.100302.epkg.Z d1e7d116d3e94c4e6927e42021fa251ae48cf579 IZ71071_04.100302.epkg.Z 5b4cd44a7a5a0e388a7fa210078ffd0259ee4479 IZ71093_09.100302.epkg.Z 88c3de0d8b25146231409b9974181a3ab06824b5 IZ71608_10.100302.epkg.Z 0c3b7157d7e1bdeb0a12bf5d4170fe7724398c9a IZ71610_11.100302.epkg.Z 688bf77366a0662461c9ce6de779c2632370274f IZ71611_01.100302.epkg.Z 8826b6f6d788ab5f79dd40935297b4dba2c483d8 IZ71613_02.100302.epkg.Z 30a25237fcc64a4a7f3f734ed72faedad41c2097 IZ71614_03.100302.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 B. 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. Fix management documentation can be found at: http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html To preview fix installation: emgr -e fix_name -p # where fix_name is the name of the # fix being previewed. To install fix package: emgr -e fix_name -X # where fix_name is the name of the # fix being installed. IMPORTANT: The fix will not take affect until any running xntpd servers have been stopped and restarted with the following commands: stopsrc -s xntpd startsrc -s xntpd C. APARS IBM has assigned the following APARs to this problem: AIX Level APAR number Service pack date -------------------------------------------------------- 5.3.8 IZ68659 5/19/10 sp10 5.3.9 IZ71093 5/19/10 sp7 5.3.10 IZ71608 5/19/10 sp4 5.3.11 IZ71610 5/19/10 sp4 6.1.1 IZ71611 4/21/10 sp8 6.1.2 IZ71613 4/21/10 sp7 6.1.3 IZ71614 4/21/10 sp4 6.1.4 IZ71071 4/21/10 sp4 Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IZ68659 http://www.ibm.com/support/docview.wss?uid=isg1IZ71093 http://www.ibm.com/support/docview.wss?uid=isg1IZ71608 http://www.ibm.com/support/docview.wss?uid=isg1IZ71610 http://www.ibm.com/support/docview.wss?uid=isg1IZ71611 http://www.ibm.com/support/docview.wss?uid=isg1IZ71613 http://www.ibm.com/support/docview.wss?uid=isg1IZ71614 http://www.ibm.com/support/docview.wss?uid=isg1IZ71071 By subscribing, you will receive periodic email alerting you to the status of the APAR, and a link to download the service pack when it becomes available. IV. WORKAROUND Remove the entry for xntpd from /etc/rc.tcpip and stop the current instance of xntpd. This can be done by running the following command: /usr/sbin/chrctcp -S -d xntpd 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. Send an email with "get key" in the subject line to: security-alert@austin.ibm.com B. Download the key from our web page: http://www.ibm.com/systems/resources/systems_p_os_aix_security_pgpkey.txt C. Download the key from a PGP Public Key Server. The key ID is: 0xF3807ECD 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 Harlan Stenn. - --------------------------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. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iD8DBQFLju46/iFOrG6YcBERAgvmAJ4/ijHPbsuOIes0iSWUZKU8/guW5gCfXOcq Okt3RGa990+zWBEJa3FJdlM= =CaYm -----END PGP SIGNATURE-----