IBM SECURITY ADVISORY First Issued: Tues Nov 3 09:00:00 CDT 2015 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc https://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc Security Bulletin: Vulnerability in bind affects AIX (CVE-2015-5722) =============================================================================== SUMMARY: ISC BIND is vulnerable to a denial of service, caused by the exit of a validating resolver due to an assertion failure in buffer.c. By parsing a malformed DNSSEC key, a remote attacker could exploit this vulnerability to cause a denial of service. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2015-5722 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by the exit of a validating resolver due to an assertion failure in buffer.c. By parsing a malformed DNSSEC key, a remote attacker could exploit this vulnerability to cause a denial of service. CVSS Base Score: 7.5 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/106089 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:C) 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 6.1.8.0 6.1.8.20 key_w_fs bos.net.tcp.client 6.1.9.0 6.1.9.45 key_w_fs bos.net.tcp.client 7.1.2.0 7.1.2.20 key_w_fs bos.net.tcp.client 7.1.3.0 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) 6.1.8.20(2.2.2.70) 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 --------------------------------------------------- 5.3.12 IV78092 N/A key_w_apar 6.1.8 IV78096 N/A key_w_apar 6.1.9 IV78091 12/04/15 SP6 key_w_apar 7.1.2 IV78094 N/A key_w_apar 7.1.3 IV78095 2/26/16 SP6 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IV78091 http://www.ibm.com/support/docview.wss?uid=isg1IV78095 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/bind_fix9.tar http://aix.software.ibm.com/aix/efixes/security/bind_fix9.tar https://aix.software.ibm.com/aix/efixes/security/bind_fix9.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 IV78092m9a.151103.epkg.Z key_w_fix 6.1.8.7 IV78096m7a.151021.epkg.Z key_w_fix 6.1.9.5 IV78091m5a.151020.epkg.Z key_w_fix 7.1.2.7 IV78094m7a.151020.epkg.Z key_w_fix 7.1.3.5 IV78095m5a.151019.epkg.Z key_w_fix VIOS Level Interim Fix (*.Z) KEY ------------------------------------------------ 2.2.2.70 IV78096m7a.151021.epkg.Z key_w_fix 2.2.3.50 IV78091m5a.151020.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf bind_fix9.tar cd bind_fix9 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 ----------------------------------------------------------------------------------------------------- 404c44a81b43cb8cacab75e732bc7c8eca27a869a137c619294fb3b91cf9f99c IV78092m9a.151103.epkg.Z key_w_csum c2d3210404653dd91298efe732cb9b87ab0db9c6470f8c1ca540482b01690013 IV78096m7a.151021.epkg.Z key_w_csum 95cb6237a23f136ae81f647d01f54a72c63594f8d8dcd4ff323523f096e01047 IV78091m5a.151020.epkg.Z key_w_csum 8b10bce53ed6e225e29c8aa3663463d8320fe798c7b02740ba3b457ad294bb56 IV78094m7a.151020.epkg.Z key_w_csum ccc6e8abe8bf25e42fb08e4754f1b3e89d60c40bc73be4cec8a24af034c84c83 IV78095m5a.151019.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/bind_advisory9.asc.sig https://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory9.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: 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: Tues Nov 3 09:00:00 CDT 2015 =============================================================================== *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.