IBM SECURITY ADVISORY First Issued: Tue May 20 08:16:08 CDT 2025 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/bind_advisory28.asc Security Bulletin: AIX is vulnerable to a denial of service due to ISC BIND =============================================================================== SUMMARY: Vulnerabilities in ISC BIND could allow a remote attacker to cause a denial of service (CVE-2024-12705, CVE-2024-11187). AIX uses ISC BIND as as part of its DNS functions. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2024-12705 https://www.cve.org/CVERecord?id=CVE-2024-12705 DESCRIPTION: Clients using DNS-over-HTTPS (DoH) can exhaust a DNS resolver's CPU and/or memory by flooding it with crafted valid or invalid HTTP/2 traffic. CVSS Base Score: 7.5 CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) CVEID: CVE-2024-11187 https://www.cve.org/CVERecord?id=CVE-2024-11187 DESCRIPTION: It is possible to construct a zone such that some queries to it will generate responses containing numerous records in the Additional section. An attacker sending many such queries can cause either the authoritative server itself or an independent resolver to use disproportionate resources processing the queries. Zones will usually need to have been deliberately crafted to attack this exposure. CVSS Base Score: 7.5 CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) AFFECTED PRODUCTS AND VERSIONS: AIX 7.2, 7.3 VIOS 3.1, 4.1 The following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY ---------------------------------------------------------- bind.rte 7.1.916.0 7.1.916.4800 key_w_fs bind.rte 7.2.916.0 7.2.916.4801 key_w_fs bind.rte 7.2.918.0 7.2.918.2800 key_w_fs bind.rte 7.3.916.0 7.3.916.4800 key_w_fs bind.rte 7.3.918.0 7.3.918.2800 key_w_fs Note: A. Latest level of BIND fileset is available from the web download site: https://www.ibm.com/resources/mrs/assets?source=aixbp 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 bind.rte REMEDIATION: A. FIXES IBM strongly recommends addressing the vulnerability now. The AIX and VIOS fixes can be downloaded via https from: https://aix.software.ibm.com/aix/efixes/security/bind_fix28.tar The fileset update has a dependency on OpenSSL 3.0. OpenSSL 3.0 may be downloaded from: https://www.ibm.com/resources/mrs/assets?source=aixbp The link above is to a tar file containing this signed advisory, install 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. To extract the fixes from the tar file: tar xvf bind_fix28.tar For AIX 7.2 and VIOS 3.1 (requires OpenSSL 3.0): tar xvf bind_fix28/72bind918.tar For AIX 7.3 and VIOS 4.1: tar xvf bind_fix28/73bind918.tar 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 the fix installation: installp -apYd . bind To install the fix package: installp -aXYd . bind 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 --------------------------------------------------------------------------------------- 433ca0d5edb9af9c063aa85ce534131911e5a59a3acb01230a413037936d2966 72bind.rte key_w_csum a926b51554425b2480fc733855aac979215846cb5adbdd92bdd766355f40f4db 73bind.rte 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: https://aix.software.ibm.com/aix/efixes/security/bind_advisory28.asc.sig B. 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: https://www.ibm.com/support/pages/managing-interim-fixes-aix 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": https://www.ibm.com/support/mynotifications Contact IBM Support for questions related to this announcement: https://ibm.com/support/ For information on how to securely verify AIX security bulletins and fixes: https://www.ibm.com/support/pages/node/6985269 To obtain the OpenSSL public key that can be used to verify the signed advisories and ifixes: Download the key from our web page: https://aix.software.ibm.com/aix/efixes/security/systems_p_os_aix_security_pubkey.txt To verify the AIX/VIOS security bulletin: Published advisory OpenSSL signature file location: https://aix.software.ibm.com/aix/efixes/security/bind_advisory28.asc.sig openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file] 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: AIX is vulnerable to denial of service due to ISC BIND https://www.ibm.com/support/pages/node/7233964 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Tue May 20 08:16:08 CDT 2025 =============================================================================== *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.