-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 IBM SECURITY ADVISORY First Issued: Tue Mar 2 09:31:41 CST 2010 | Updated: Mon Mar 29 13:09:51 CDT 2010 | Added VIOS information | Fixed prerequisite levels 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 | VIOS 1.5, 2.1, 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 | Note: To use the following commands on VIOS you must first | execute: | oem_setup_env 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 5.3.8.0 5.3.8.11 | bos.net.tcp.client 5.3.9.0 5.3.9.7 | bos.net.tcp.client 5.3.10.0 5.3.10.2 | bos.net.tcp.client 5.3.11.0 5.3.11.2 | bos.net.tcp.client 6.1.4.0 6.1.4.3 | bos.net.tcp.client 6.1.1.0 6.1.1.7 | bos.net.tcp.client 6.1.2.0 6.1.2.6 | bos.net.tcp.client 6.1.3.0 6.1.3.3 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 VIOS Level Fix ------------------------------------------------------------------- | 5.3.8 1.5.2 IZ68659_08.100329.epkg.Z | 5.3.9 IZ71093_09.100329.epkg.Z | 5.3.10 IZ71608_10.100329.epkg.Z | 5.3.11 IZ71610_11.100329.epkg.Z 6.1.1 IZ71611_01.100302.epkg.Z | 6.1.2 2.1.0 IZ71613_02.100302.epkg.Z | 6.1.3 2.1.1 IZ71614_03.100302.epkg.Z | 6.1.4 2.1.2 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 ------------------------------------------------------------------ | 91840ff2428fbec53effd26b200ae51a312dea5f IZ68659_08.100329.epkg.Z d1e7d116d3e94c4e6927e42021fa251ae48cf579 IZ71071_04.100302.epkg.Z | 9f353343cc3a12eb5e87826ca4622c5babb40903 IZ71093_09.100329.epkg.Z | d71db135676b701ad87d3c3954bf6656e47fffba IZ71608_10.100329.epkg.Z | 58bef50778cf5c4d3b7b39dfdaf11d0d7706894b IZ71610_11.100329.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. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (AIX) iD8DBQFLsO55xvGNyvOAfs0RAhZGAJ9EXq8DmYANQNZCimDl5r8ANP1p0QCfRf8F RrWm6uxP1vVOQIfZ6kV6/vU= =wTDb -----END PGP SIGNATURE-----