IBM SECURITY ADVISORY First Issued: Fri Aug 21 15:48:15 CDT 2020 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/bind_advisory17.asc https://aix.software.ibm.com/aix/efixes/security/bind_advisory17.asc ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory17.asc Security Bulletin: Vulnerabilities in BIND affect AIX (CVE-2020-8616 and CVE-2020-8617) =============================================================================== SUMMARY: There are vulnerabilities in BIND that affect AIX. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2020-8616 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8616 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8616 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by the failure to limit the number of fetches performed when processing referrals. By using specially crafted referrals, a remote attacker could exploit this vulnerability to cause the recursing server to issue a very large number of fetches in an attempt to process the referral. CVSS Base Score: 8.6 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/182126 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H) CVEID: CVE-2020-8617 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8617 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8617 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by a logic error in code which checks TSIG validity. A remote attacker could exploit this vulnerability to trigger an assertion failure in tsig.c. CVSS Base Score: 7.5 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/182127 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) AFFECTED PRODUCTS AND VERSIONS: AIX 7.1, 7.2 VIOS 2.2, 3.1 The following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY --------------------------------------------------------- bos.net.tcp.client 6.1.9.0 6.1.9.404 key_w_fs bos.net.tcp.client 7.1.5.0 7.1.5.35 key_w_fs bos.net.tcp.bind_utils 7.2.2.0 7.2.2.18 key_w_fs bos.net.tcp.bind_utils 7.2.3.0 7.2.3.16 key_w_fs bos.net.tcp.bind_utils 7.2.4.0 7.2.4.1 key_w_fs 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 ----------------------------------------------------- 7.1.5 IJ25924 ** SP07-2037 key_w_apar 7.2.2 IJ25925 ** N/A key_w_apar 7.2.3 IJ25926 ** SP06-2038 key_w_apar 7.2.4 IJ25927 ** SP03-2038 key_w_apar VIOS Level APAR Availability SP KEY ---------------------------------------------------- 2.2.6 IJ26021 ** N/A key_w_apar 3.1.0 IJ25926 ** 3.1.0.50 key_w_apar 3.1.1 IJ25927 ** 3.1.1.30 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/pages/apar/IJ25924 http://www.ibm.com/support/pages/apar/IJ25925 http://www.ibm.com/support/pages/apar/IJ25926 http://www.ibm.com/support/pages/apar/IJ25927 http://www.ibm.com/support/pages/apar/IJ26021 https://www.ibm.com/support/pages/apar/IJ25924 https://www.ibm.com/support/pages/apar/IJ25925 https://www.ibm.com/support/pages/apar/IJ25926 https://www.ibm.com/support/pages/apar/IJ25927 https://www.ibm.com/support/pages/apar/IJ26021 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 AIX and VIOS fixes are available. The AIX and VIOS fixes can be downloaded via ftp or http from: ftp://aix.software.ibm.com/aix/efixes/security/bind_fix17.tar http://aix.software.ibm.com/aix/efixes/security/bind_fix17.tar https://aix.software.ibm.com/aix/efixes/security/bind_fix17.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 ---------------------------------------------- 7.1.5.4 IJ25924s6a.200708.epkg.Z key_w_fix 7.1.5.5 IJ25924s6a.200708.epkg.Z key_w_fix 7.1.5.6 IJ25924s6a.200708.epkg.Z key_w_fix 7.2.2.4 IJ25925s6a.200708.epkg.Z key_w_fix 7.2.2.5 IJ25925s6a.200708.epkg.Z key_w_fix 7.2.2.6 IJ25925s6a.200708.epkg.Z key_w_fix 7.2.3.3 IJ25926s5a.200708.epkg.Z key_w_fix 7.2.3.4 IJ25926s5a.200708.epkg.Z key_w_fix 7.2.3.5 IJ25926s5a.200708.epkg.Z key_w_fix 7.2.4.0 IJ25927s2a.200708.epkg.Z key_w_fix 7.2.4.1 IJ25927s2a.200708.epkg.Z key_w_fix 7.2.4.2 IJ25927s2a.200708.epkg.Z key_w_fix Please note that the above table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.2.3.5 is AIX 7200-03-05. Please reference the Affected Products and Version section above for help with checking installed fileset levels. VIOS Level Interim Fix (*.Z) KEY ----------------------------------------------- 2.2.6.40 IJ26021sDa.200708.epkg.Z key_w_fix 2.2.6.41 IJ26021sDa.200708.epkg.Z key_w_fix 2.2.6.50 IJ26021sDa.200708.epkg.Z key_w_fix 2.2.6.51 IJ26021sDa.200708.epkg.Z key_w_fix 2.2.6.60 IJ26021sDa.200708.epkg.Z key_w_fix 2.2.6.61 IJ26021sDa.200708.epkg.Z key_w_fix 2.2.6.65 IJ26021sDa.200708.epkg.Z key_w_fix 3.1.0.20 IJ25926s5a.200708.epkg.Z key_w_fix 3.1.0.30 IJ25926s5a.200708.epkg.Z key_w_fix 3.1.0.40 IJ25926s5a.200708.epkg.Z key_w_fix 3.1.1.0 IJ25927s2a.200708.epkg.Z key_w_fix 3.1.1.10 IJ25927s2a.200708.epkg.Z key_w_fix 3.1.1.20 IJ25927s2a.200708.epkg.Z key_w_fix 3.1.1.21 IJ25927s2a.200708.epkg.Z key_w_fix 3.1.1.22 IJ25927s2a.200708.epkg.Z key_w_fix 3.1.1.25 IJ25927s2a.200708.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf bind_fix17.tar cd bind_fix17 Verify you have retrieved the fixes intact: The checksums below were generated using the "openssl dgst -sha256 [filename]" command as the following: openssl dgst -sha256 filename KEY ----------------------------------------------------------------------------------------------------- 1b952357d1691d203c13d888760553743269a7b84e3432131bab9a6a919a53a7 IJ25924s6a.200708.epkg.Z key_w_csum 5f221cb2ee211f02256d5e88c8a5962aed7a97ae6683a6eaf3724fe81eef0fe8 IJ25925s6a.200708.epkg.Z key_w_csum e9b46105c1713fc1944b55fd3d637d912feaec439865bcc23a91c8f739ea5535 IJ25926s5a.200708.epkg.Z key_w_csum d8a02e72780156eca420977627bb7c80455afc6e4b3d40a0e5cb5c6a72c4cfaa IJ25927s2a.200708.epkg.Z key_w_csum 974e499efc70808300e1e7bb7af7706765a6ccd040c5e76944a52b727c0f5dd7 IJ26021sDa.200708.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 Support at http://ibm.com/support/ and describe the discrepancy. openssl dgst -sha1 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file] openssl dgst -sha1 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file] Published advisory OpenSSL signature file location: http://aix.software.ibm.com/aix/efixes/security/bind_advisory17.asc.sig https://aix.software.ibm.com/aix/efixes/security/bind_advisory17.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory17.asc.sig C. FIX AND INTERIM FIX INSTALLATION 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 Contact IBM Support for questions related to this announcement: http://ibm.com/support/ https://ibm.com/support/ To obtain the OpenSSL public key that can be used to verify the signed advisories and ifixes: Download the key from our web page: ftp://ftp.software.ibm.com/systems/power/AIX/systems_p_os_aix_security_pubkey.txt 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 RELATED INFORMATION: IBM Secure Engineering Web Portal http://www.ibm.com/security/secure-engineering/bulletins.html IBM Product Security Incident Response Blog https://www.ibm.com/blogs/psirt/ Security Bulletin: Vulnerabilities in BIND affect AIX https://www.ibm.com/support/pages/node/6320325 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Fri Aug 21 15:48:15 CDT 2020 =============================================================================== *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.