IBM SECURITY ADVISORY First Issued: Thu Aug 13 10:35:36 CDT 2015 |Updated: Mon Aug 17 09:11:49 CDT 2015 |Update: Added AIX 5.3 vulnerability information The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/bind9_advisory8.asc https://aix.software.ibm.com/aix/efixes/security/bind9_advisory8.asc ftp://aix.software.ibm.com/aix/efixes/security/bind9_advisory8.asc Security Bulletin: Vulnerability in BIND affects AIX (CVE-2015-5477) =============================================================================== SUMMARY: BIND vulnerability disclosed by Internet Systems Consortium (ISC) affects AIX. AIX has addressed this CVE. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2015-5477 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an error in the handling of TKEY queries. By sending specially-crafted packets, a remote attacker could exploit this vulnerability to cause a REQUIRE assertion failure. CVSS Base Score: 7.5 CVSS Temporal Score: See  https://exchange.xforce.ibmcloud.com/vulnerabilities/105120 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) AFFECTED PRODUCTS AND VERSIONS: | AIX 5.3, 6.1, 7.1 VIOS 2.2.x The following AIX fileset levels are vulnerable: AIX Fileset Lower Level Upper Level KEY -------------------------------------------------------- | bos.net.tcp.client 5.3.12.0 5.3.12.10 key_w_fs bos.net.tcp.client 6.1.0.0 6.1.8.19 key_w_fs bos.net.tcp.client 6.1.0.0 6.1.9.45 key_w_fs bos.net.tcp.client 7.1.0.0 7.1.2.19 key_w_fs bos.net.tcp.client 7.1.0.0 7.1.3.45 key_w_fs AIX Fileset (VIOS) Lower Level Upper Level ------------------------------------------------------------ bos.net.tcp.client 6.1.0.0(2.2.0.0) 6.1.8.19(2.2.2.6) bos.net.tcp.client 6.1.0.0(2.2.0.0) 6.1.9.45(2.2.3.50) 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.net.tcp.client REMEDIATION: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY --------------------------------------------------- 6.1.9 IV75692 12/04/15 SP6 key_w_apar 7.1.3 IV75693 2/26/16 SP6 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IV75692 http://www.ibm.com/support/docview.wss?uid=isg1IV75693 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/bind9_fix8.tar http://aix.software.ibm.com/aix/efixes/security/bind9_fix8.tar https://aix.software.ibm.com/aix/efixes/security/bind9_fix8.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 ------------------------------------------------ | 5.3.12.9 IV75966s9a.150813.epkg.Z key_w_fix 6.1.8.6 IV75694s6a.150803.epkg.Z key_w_fix 6.1.9.5 IV75692s5a.150803.epkg.Z key_w_fix 7.1.2.6 IV75690s6a.150803.epkg.Z key_w_fix 7.1.3.5 IV75693s5a.150803.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf bind9_fix8.tar cd bind9_fix8 Verify you have retrieved the fixes intact: The checksums below were generated using the "openssl dgst -sha256 file" command as the following: openssl dgst -sha256 filename KEY ---------------------------------------------------------------------------------------------------- | 043af7d6494326d47b3d35a2a1b9785ea7df4b6d6e56282a251d52d5579d67a1 IV75966s9a.150813.epkg.Z key_w_csum af10c7895263c219514f1281617c082dbef35ec5076fa6744e3726517eb322dc IV75694s6a.150803.epkg.Z key_w_csum c8c76aed365993102386e9a01b825673fe5684e0b549ae72abf6f1fb9cd55fba IV75692s5a.150803.epkg.Z key_w_csum e574f9da379cb8eb8709cd7f87243cb44b75cc8462a02144973d4def4b7021c4 IV75690s6a.150803.epkg.Z key_w_csum ad3665e58be16caf9b21f75f788431181c3d79b057129bf4da05690c0bed9304 IV75693s5a.150803.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/bind9_advisory8.asc.sig https://aix.software.ibm.com/aix/efixes/security/bind9_advisory8.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/bind9_advisory8.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. You should verify applying this configuration change does not cause any compatibility issues. If you change the default setting after applying the fix, you will expose yourself to the attack described above. IBM recommends that you review your entire environment to identify other areas where you have enabled the Diffie-Hellman key-exchange protocol used in TLS and take appropriate mitigation and remediation actions. WORKAROUNDS AND MITIGATIONS: None. =============================================================================== CONTACT US: 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 Guide: http://www.first.org/cvss/cvss-guide.html On-line Calculator V2: http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2 ACKNOWLEDGEMENTS: None CHANGE HISTORY: First Issued: Thu Aug 13 10:35:36 CDT 2015 | Updated: Mon Aug 17 09:11:49 CDT 2015 | Update: Added AIX 5.3 vulnerability information =============================================================================== *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.