IBM SECURITY ADVISORY First Issued: Mon Nov 18 15:17:14 CST 2024 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/bind_advisory27.asc Security Bulletin: AIX is vulnerable to a denial of service due to ISC BIND =============================================================================== SUMMARY: Multiple vulnerabilities in ISC BIND could allow a remote attacker to cause a denial of service (CVE-2024-0760, CVE-2024-1737, CVE-2024-4076, CVE-2024-1975). AIX uses ISC BIND as part of its DNS functions. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2024-0760 https://www.cve.org/CVERecord?id=CVE-2024-0760 DESCRIPTION: ISC BIND is vulnerable to a denial of service. By sending a flood of DNS messages over TCP, a remote attacker could exploit this vulnerability to cause the server to become unstable. CVSS Base Score: 7.5 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) CVEID: CVE-2024-1737 https://www.cve.org/CVERecord?id=CVE-2024-1737 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an error when content is being added or updated in resolver caches and authoritative zone databases that hold significant numbers of RRs for the same hostname (of any RTYPE). By processing queries, a remote attacker could exploit this vulnerability to cause the database to slow down. CVSS Base Score: 7.5 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) CVEID: CVE-2024-4076 https://www.cve.org/CVERecord?id=CVE-2024-4076 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an error when serving both stale cache data and authoritative zone content. By sending queries, a remote attacker could exploit this vulnerability to cause an assertion failure. CVSS Base Score: 7.5 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) CVEID: CVE-2024-1975 https://www.cve.org/CVERecord?id=CVE-2024-1975 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an error if a server hosts a zone containing a "KEY" Resource Record, or a resolver DNSSEC-validates a "KEY" Resource Record from a DNSSEC-signed domain in cache. By sending a stream of SIG(0) signed requests, a remote attacker could exploit this vulnerability to exhaust all available CPU resources. CVSS Base Score: 7.5 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 7.2, 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 7.3.916.0 7.3.916.4800 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 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_fix27.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_fix27.tar For AIX 7.2 and VIOS 3.1 (requires OpenSSL 3.0): tar xvf bind_fix27/72bind918.tar For AIX 7.3 and VIOS 4.1: tar xvf bind_fix27/73bind918.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 --------------------------------------------------------------------------------------- dba6637bf313be11f6c3a77b82ad7c210eeb54ad9c01b9a7ba0d619b6a4acac8 72bind.rte key_w_csum 59d0d2fc1f24f86071472f880ee559ef42ef60dfc357a1ffffb26f08f446dbfd 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_advisory27.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_advisory27.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/7176451 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Mon Nov 18 15:17:14 CST 2024 =============================================================================== *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.