IBM SECURITY ADVISORY First Issued: Fri Feb 3 10:20:44 CST 2012 | Updated: Mon Feb 6 08:56:46 CST 2012 | Updated AIX 53 TL 12 ifix | Updated: Wed Feb 8 16:18:36 CST 2012 | Added VIOS ifixes | Updated: Wed Feb 29 16:32:13 CST 2012 | Added 6.1 TL7 SP3 and 7.1 TL1 SP3 ifixes | Updated: Wed Mar 21 13:44:22 CDT 2012 | Fix AIX Level in ifix section | Updated: Thu Dec 12 12:55:11 CST 2013 | Update: 1. Added KEYs for parsing purposes | 2. Moved to OpenSSL signature The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/large_send_advisory.asc ftp://aix.software.ibm.com/aix/efixes/security/large_send_advisory.asc =============================================================================== VULNERABILITY SUMMARY VULNERABILITY: Vulnerability in AIX TCP stack PLATFORMS: AIX 5.3, 6.1, and 7.1 releases SOLUTION: Apply the fix as described below. THREAT: TCP network packet denial of service CVE Number: CVE-2012-0194 CVSS=7.1 Reboot required? YES Workarounds? YES Protected by FPM? NO Protected by SED? NO =============================================================================== DETAILED INFORMATION I. DESCRIPTION AIX could allow a remote attacker to cause a denial of service, caused by an error when the TCP large send offload option is enabled on a network interface. By sending a specially-crafted sequence of packets, an attacker could exploit this vulnerability to cause a kernel panic. II. CVSS CVSS Base Score: 7.1 CVSS Temporal Score: See http://xforce.iss.net/xforce/xfdb/72562 for the current score CVSS Environmental Score*: Undefined CVSS String: (AV:n/AC:m/Au:n/C:n/I:n/A:c) III. 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 KEY --------------------------------------------------------- bos.net.tcp.client 5.3.12.0 5.3.12.5 key_w_fs bos.net.tcp.client 6.1.5.0 6.1.5.8 key_w_fs bos.net.tcp.client 6.1.6.0 6.1.6.17 key_w_fs bos.net.tcp.client 6.1.7.0 6.1.7.3 key_w_fs bos.net.tcp.client 7.1.0.0 7.1.0.17 key_w_fs bos.net.tcp.client 7.1.1.0 7.1.1.3 key_w_fs IV. SOLUTIONS A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR number Availability KEY ----------------------------------------------------------- 5.3.12 IV13827 TBD sp6 key_w_apar 6.1.5 IV13751 TBD sp9 key_w_apar 6.1.6 IV13820 TBD sp8 key_w_apar 6.1.7 IV14209 TBD sp4 key_w_apar 7.1.0 IV14210 TBD sp5 key_w_apar 7.1.1 IV14211 TBD sp4 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IV13827 http://www.ibm.com/support/docview.wss?uid=isg1IV13751 http://www.ibm.com/support/docview.wss?uid=isg1IV13820 http://www.ibm.com/support/docview.wss?uid=isg1IV14209 http://www.ibm.com/support/docview.wss?uid=isg1IV14210 http://www.ibm.com/support/docview.wss?uid=isg1IV14211 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 available. The fixes can be downloaded via ftp from: ftp://aix.software.ibm.com/aix/efixes/security/large_send_fix.tar The link above is to a tar file containing this signed advisory, fix packages, and OpenSSL 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 Interim Fix (*.Z) KEY ------------------------------------------------------------------- | 5.3.12.5 53XSP5_IV13827s05.120204.epkg.Z key_w_fix 6.1.5.7 61JSP7_IV13751s07.120126.epkg.Z key_w_fix | 6.1.6.6 61NSP6_IV13820s06.120126.epkg.Z key_w_fix 6.1.7.2 61QS02_IV14209s02.120126.epkg.Z key_w_fix | 6.1.7.3 IV14209s03.120228.epkg.Z key_w_fix | 7.1.0.4 71BSP4_IV14210s04.120129.epkg.Z key_w_fix | 7.1.1.2 71DSP2_IV14211s02.120126.epkg.Z key_w_fix | 7.1.1.3 IV14211s03.120228.epkg.Z key_w_fix | VIOS Level Interim Fix (*.Z) | ------------------------------------------------------------------- | 2.2.1.3 61QS02_IV14209s02.120126.epkg.Z | 2.2.0.13-FP-24 SP-03 61NVIOS_IV13820s.120204.epkg.Z | 2.1.3.10-FP23 61JVIOS_IV13751s01.120206.epkg.Z | 2.1.2.13-FP-22.1 SP-02 61HVIOS_IV13751s03.120204.epkg.Z | 2.1.1.10-FP21 61FVIOS_IV13751s1.120205.epkg.Z To extract the fixes from the tar file: tar xvf large_send_fix.tar cd large_send_fix Verify you have retrieved the fixes intact: The checksums below were generated using the "csum -h SHA1" (sha1sum) command is the followng: csum -h SHA1 (sha1sum) filename ------------------------------------------------------------------ | 54fbed88774e7f3602468da3eb2879c90abb95fa 53XSP5_IV13827s05.120204.epkg.Z 37aca7ad354a8e0775152f6801c0d9790a990782 61JSP7_IV13751s07.120126.epkg.Z 637048a0ab3764d712a837815cccf355bf4be245 61NSP6_IV13820s06.120126.epkg.Z 12fddcb7e3ee87144a8ed8008c4e40ea70df8262 61QS02_IV14209s02.120126.epkg.Z 246e09b69f741a1c552042c065bfc0854167c5f3 71BSP4_IV14210s04.120129.epkg.Z 5945422d284849fd2f268a5b54a62eeb2fcae18b 71DSP2_IV14211s02.120126.epkg.Z | 5925c360835ac7368e7b501c564da5a35074af57 61FVIOS_IV13751s1.120205.epkg.Z | b1ef32feaea061348938bc0bea7fd14fd512d865 61HVIOS_IV13751s03.120204.epkg.Z | 6ad88c439bc0528ce1032582eb13525f79ad8406 61JVIOS_IV13751s01.120206.epkg.Z | ac3f5ce1a620d58b38727b54ad5ae386e5faa373 61NVIOS_IV13820s.120204.epkg.Z | 3d28fef37a9787677de8125e2c231d955cff5222 IV14209s03.120228.epkg.Z | 9d418db8c0c988f518344d29ae58502cb373d1db IV14211s03.120228.epkg.Z To verify the sum, use the text of this advisory as input to sha1sum. For example: csum -h SHA1 -i Advisory.asc sha1sum -c Advisory.asc These sums should match exactly. The OpenSSL 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 at security-alert@austin.ibm.com and describe the discrepancy. openssl dgst -sha1 -verify AIX_PSIRT_pub.asc -signature file.asc.sig file.asc C. FIX AND 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. 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. 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. V. WORKAROUNDS Adjust the lowest value from the common path MTUs table based on customer configuration. Turn off large send function (may have performance impact) Turn off path MTU discovery (may have performance impact) VI. OBTAINING FIXES AIX security fixes can be downloaded from: 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. VII. CONTACT INFORMATION If you would like to receive AIX Security Advisories via email, 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 OpenSSL public key that can be used to verify the signed advisories and ifixes: Download the key from our web page: http://www.ibm.com/systems/resources/systems_p_os_aix_security_pubkey.txt To request 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 a PGP Public Key Server. The key ID is: 0x28BFAA12 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. VIII. REFERENCES: Note: Keywords labeled as KEY in this document are used for parsing purposes. Complete CVSS Guide: http://www.first.org/cvss/cvss-guide.html On-line Calculator V2: http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2 X-Force Vulnerability Database: http://xforce.iss.net/xforce/xfdb/72562 CVE-2012-0194: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0194 *The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Flash. Note: According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES "AS IS" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.