IBM SECURITY ADVISORY First Issued: Mon Feb 22 08:06:13 CST 2016 |Updated: Thu Aug 11 12:11:35 CDT 2016 |Update: Changed the iFix name for the AIX 7.1.3 fix. No changes relevant | to AIX 7.1.3 were made to the fix. The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc ftp://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc Security Bulletin: Vulnerabilities in LibXML2 affect AIX CVE-2015-7941 CVE-2015-7942 CVE-2015-8241 =============================================================================== SUMMARY: There are multiple vulnerabilities in LibXML2 that impact AIX. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2015-7941 DESCRIPTION: Libxml2 is vulnerable to a denial of service, caused by a heap-based buffer overflow in the xmlParseEntityDecl or xmlParseConditionalSections function. By using a specially-crafted XML data, a remote attacker could exploit this vulnerability to trigger an out-of-bounds read and cause the system to crash. CVSS Base Score: 4.3 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/108071 for more information. CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L) CVEID: CVE-2015-7942 DESCRIPTION: Libxml2 is vulnerable to a denial of service, caused by a heap-based buffer overflow in the xmlParseConditionalSections function. By using a specially-crafted XML data, a remote attacker could exploit this vulnerability to trigger an out-of-bounds read and cause the system to crash. CVSS Base Score: 4.3 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/108073 for more information. CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L) CVEID: CVE-2015-8241 DESCRIPTION: libxml2 is vulnerable to a buffer overflow, caused by improper bounds checking by the XML parser in xmlNextChar. By using a malformed XML file, a local attacker could overflow a buffer and execute arbitrary code on the system or cause the application to crash. CVSS Base Score: 5.9 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/108169 for more information. CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L) AFFECTED PRODUCTS AND VERSIONS: AIX 5.3, 6.1, 7.1, 7.2 VIOS 2.2.x The following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY ----------------------------------------------------- bos.rte.control 5.3.12.0 5.3.12.9 key_w_fs bos.rte.control 6.1.9.0 6.1.9.100 key_w_fs bos.rte.control 7.1.3.0 7.1.3.46 key_w_fs bos.rte.control 7.1.4.0 7.1.4.0 key_w_fs bos.rte.control 7.2.0.0 7.2.0.0 key_w_fs Note: to find out whether the affected filesets are installed on your systems, refer to the lslpp command found in AIX user's guide. Example: lslpp -L | grep -i bos.rte.control REMEDIATION: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY ------------------------------------------------ 5.3.12 IV80617 N/A N/A key_w_apar 6.1.9 IV80588 5/20/16 SP7 key_w_apar 7.1.4 IV80586 5/20/16 SP2 key_w_apar 7.2.0 IV80616 5/20/16 SP2 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IV80617 http://www.ibm.com/support/docview.wss?uid=isg1IV80588 http://www.ibm.com/support/docview.wss?uid=isg1IV80586 http://www.ibm.com/support/docview.wss?uid=isg1IV80616 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 or http from: ftp://aix.software.ibm.com/aix/efixes/security/libxml2_fix2.tar http://aix.software.ibm.com/aix/efixes/security/libxml2_fix2.tar https://aix.software.ibm.com/aix/efixes/security/libxml2_fix2.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.x IV80617s9a.160120.epkg.Z key_w_fix 6.1.9.x IV80588s6a.160121.epkg.Z key_w_fix | 7.1.3.x IV80586s1a.160713.epkg.Z key_w_fix 7.1.4.x IV80586s1a.160713.epkg.Z key_w_fix 7.2.0.x IV80616s1a.160722.epkg.Z key_w_fix VIOS Level Interim Fix (*.Z) KEY ----------------------------------------------- 2.2.4.0 IV80588s6a.160121.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf libxml2_fix2.tar cd libxml2_fix2 Verify you have retrieved the fixes intact: The checksums below were generated using the "openssl dgst -sha256 file" command as the followng: openssl dgst -sha256 filename KEY ----------------------------------------------------------------------------------------------------- 72045867e0660eb92ef58660f4594746d7d50643fefe72c8f8e53b77f80cdd18 IV80586s1a.160713.epkg.Z key_w_csum 10ebb3487e540b54cd0620cfcd23c7d8ca68b789ad8bf98c93686da239ccedee IV80588s6a.160121.epkg.Z key_w_csum 9a013e6a7f82459eafd6380c0f4b1bd2fc974178944ee277e6e3eeaf4c235072 IV80616s1a.160722.epkg.Z key_w_csum 8cff222b94a53ee6f2ddace7c6257280734c0396be5757309759d4ae2003be90 IV80617s9a.160120.epkg.Z key_w_csum 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 -signature .sig openssl dgst -sha1 -verify -signature .sig Published advisory OpenSSL signature file location: http://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc.sig https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc.sig 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; however, IBM does fully support them. 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. WORKAROUNDS AND MITIGATIONS: None. =============================================================================== CONTACT US: Note: Keywords labeled as KEY in this document are used for parsing purposes. If you would like to receive AIX Security Advisories via email, please visit "My Notifications": http://www.ibm.com/support/mynotifications To view previously issued advisories, please visit: http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq 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 obtain the PGP public key that can be used to communicate securely with the AIX Security Team via security-alert@austin.ibm.com you can either: A. Download the key from our web page: http://www.ibm.com/systems/resources/systems_p_os_aix_security_pgppubkey.txt 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. REFERENCES: Complete CVSS v3 Guide: http://www.first.org/cvss/user-guide On-line Calculator v3: http://www.first.org/cvss/calculator/3.0 ACKNOWLEDGEMENTS: None CHANGE HISTORY: First Issued: Mon Feb 22 08:06:13 CST 2016 Updated: Fri May 27 08:25:24 CDT 2016 Update: Fix added for AIX 7.1.3.6. Updated: Tue Jul 5 11:30:23 CDT 2016 Update: Changed impacted upper level fileset for AIX 7.1.4 from: bos.rte.control 7.1.4.1 to: bos.rte.control 7.1.4.0 The new upper fileset level appropriately reflects that AIX 7.1 TL4 SP2 is not vulnerable. Updated: Fri Jul 22 13:11:47 CDT 2016 Update: Changed impacted upper level fileset for AIX 7.2.0 from: bos.rte.control 7.2.0.1 to: bos.rte.control 7.2.0.0 The new upper fileset level appropriately reflects that AIX 7.2 TL0 SP2 is not vulnerable. New iFixes issued for AIX 7.1 TL4 and 7.2 TL0 with corrected upper level fileset checks. Updated: Thu Jul 28 09:02:05 CDT 2016 Update: Clarified that many of the iFixes work across TLs, indepedent of SP. | Updated: Thu Aug 11 12:11:35 CDT 2016 | Update: Changed the iFix name for the AIX 7.1.3 fix. No changes relevant | to AIX 7.1.3 were made to the fix. =============================================================================== *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 Security Bulletin. Disclaimer 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.