IBM SECURITY ADVISORY First Issued: Tue Mar 1 08:41:32 CST 2022 |Updated: Wed Mar 16 11:31:17 CDT 2022 |Update: New iFixes provided for all AIX and VIOS levels. | The previous iFixes were not cumulative, and the new iFixes are | intended to supplant the previous fixes. The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/bind_advisory20.asc https://aix.software.ibm.com/aix/efixes/security/bind_advisory20.asc ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory20.asc Security Bulletin: Vulnerability in BIND affects AIX (CVE-2021-25219) =============================================================================== SUMMARY: There is a vulnerability in BIND that affects AIX. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2021-25219 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-25219 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-25219 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by a flaw in response processing. By abusing a lame cache, an attacker could exploit this vulnerability to cause a named resolver to spend most of its CPU time on managing and checking the lame cache and severely degrade resolver performance. CVSS Base Score: 5.3 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/212375 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:L) AFFECTED PRODUCTS AND VERSIONS: AIX 7.1, 7.2, 7.3 VIOS 3.1 The following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY --------------------------------------------------------- bos.net.tcp.server 7.1.5.0 7.1.5.35 key_w_fs bos.net.tcp.client 7.1.5.0 7.1.5.40 key_w_fs bos.net.tcp.bind 7.2.4.0 7.2.4.1 key_w_fs bos.net.tcp.bind_utils 7.2.4.0 7.2.4.3 key_w_fs bos.net.tcp.bind 7.2.5.0 7.2.5.1 key_w_fs bos.net.tcp.bind_utils 7.2.5.0 7.2.5.2 key_w_fs bos.net.tcp.bind 7.2.5.100 7.2.5.100 key_w_fs bos.net.tcp.bind_utils 7.2.5.100 7.2.5.100 key_w_fs bos.net.tcp.bind 7.3.0.0 7.3.0.0 key_w_fs bos.net.tcp.bind_utils 7.3.0.0 7.3.0.0 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.server REMEDIATION: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY ----------------------------------------------------- 7.1.5 IJ37222 ** SP10 key_w_apar 7.2.4 IJ37225 ** SP06 key_w_apar 7.2.5 IJ37223 ** SP04 key_w_apar 7.3.0 IJ37226 ** SP02 key_w_apar VIOS Level APAR Availability SP KEY ----------------------------------------------------- 3.1.1 IJ37225 ** 3.1.1.60 key_w_apar 3.1.2 IJ37224 ** 3.1.2.40 key_w_apar 3.1.3 IJ37223 ** 3.1.3.20 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/pages/apar/IJ37222 http://www.ibm.com/support/pages/apar/IJ37223 http://www.ibm.com/support/pages/apar/IJ37224 http://www.ibm.com/support/pages/apar/IJ37225 http://www.ibm.com/support/pages/apar/IJ37226 https://www.ibm.com/support/pages/apar/IJ37222 https://www.ibm.com/support/pages/apar/IJ37223 https://www.ibm.com/support/pages/apar/IJ37224 https://www.ibm.com/support/pages/apar/IJ37225 https://www.ibm.com/support/pages/apar/IJ37226 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_fix20.tar http://aix.software.ibm.com/aix/efixes/security/bind_fix20.tar https://aix.software.ibm.com/aix/efixes/security/bind_fix20.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 ---------------------------------------------- | 7.1.5.7 IJ37222m9c.220315.epkg.Z key_w_fix | 7.1.5.8 IJ37222m9c.220315.epkg.Z key_w_fix | 7.1.5.9 IJ37222m9c.220315.epkg.Z key_w_fix | 7.2.4.3 IJ37225m5c.220315.epkg.Z key_w_fix | 7.2.4.4 IJ37225m5c.220315.epkg.Z key_w_fix | 7.2.4.5 IJ37225m5c.220315.epkg.Z key_w_fix | 7.2.5.1 IJ37224m3c.220315.epkg.Z key_w_fix | 7.2.5.2 IJ37224m3c.220315.epkg.Z key_w_fix | 7.2.5.3 IJ37224m3c.220315.epkg.Z key_w_fix | 7.3.0.1 IJ37226s1b.220315.epkg.Z key_w_fix Please note that the above table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.2.5.2 is AIX 7200-05-02. Please reference the Affected Products and Version section above for help with checking installed fileset levels. VIOS Level Interim Fix (*.Z) KEY ----------------------------------------------- | 3.1.1.30 IJ37225m5c.220315.epkg.Z key_w_fix | 3.1.1.40 IJ37225m5c.220315.epkg.Z key_w_fix | 3.1.1.50 IJ37225m5c.220315.epkg.Z key_w_fix | 3.1.2.10 IJ37224m3c.220315.epkg.Z key_w_fix | 3.1.2.21 IJ37224m3c.220315.epkg.Z key_w_fix | 3.1.3.10 IJ37224m3c.220315.epkg.Z key_w_fix | 3.1.3.14 IJ37224m3c.220315.epkg.Z key_w_fix The above fixes are cumulative and address previously issued AIX/VIOS BIND security bulletins. To extract the fixes from the tar file: tar xvf bind_fix20.tar cd bind_fix20 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 ----------------------------------------------------------------------------------------------------- | c97ca6a6f08834de85adf24854956cb23cc948b5fab83b87ed9314b49fedb97d IJ37222m9c.220315.epkg.Z key_w_csum | 1b664c2db58503d69141d34e5b11165ce110d7b5150b228c9cd4ba6172094042 IJ37224m3c.220315.epkg.Z key_w_csum | d0af2eab502a4ed848326db6d4af6680ad4fa015225cea58aacc807b8ff3b0f8 IJ37225m5c.220315.epkg.Z key_w_csum | 6dab0239b497eab26d75a2b8cf5715b9d4c74cb10a1ae835b229dbf5037c12c0 IJ37226s1b.220315.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 -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file] openssl dgst -sha256 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file] Published advisory OpenSSL signature file location: http://aix.software.ibm.com/aix/efixes/security/bind_advisory20.asc.sig https://aix.software.ibm.com/aix/efixes/security/bind_advisory20.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory20.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: Vulnerability in BIND affects AIX (CVE-2021-25219) https://www.ibm.com/support/pages/node/6560382 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Tue Mar 1 08:41:32 CST 2022 | Updated: Wed Mar 16 11:31:17 CDT 2022 | Update: New iFixes provided for all AIX and VIOS levels. | The previous iFixes were not cumulative, and the new iFixes are | intended to supplant the previous fixes. =============================================================================== *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.