IBM SECURITY ADVISORY First Issued: Thu Sep 7 13:08:07 CDT 2023 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/bind_advisory24.asc Security Bulletin: AIX is vulnerable to denial of service due to ISC BIND (CVE-2023-2828) =============================================================================== SUMMARY: A vulnerability in ISC BIND could allow a remote attacker to cause a denial of service (CVE-2023-2828). AIX uses ISC BIND as part of its DNS functions. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2023-2828 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2828 DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by a flaw that allows the named's configured cache size limit to be significantly exceeded. By querying the resolver for specific RRsets in a certain order, a remote attacker could exploit this vulnerability to exhaust all memory on the host. CVSS Base Score: 7.5 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/258607 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 7.2, 7.3 VIOS 3.1 The following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY ---------------------------------------------------------- bind.rte 7.1.916.0 7.1.916.2602 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: FIXES IBM strongly recommends addressing the vulnerability now. AIX and VIOS fixes are available. The fixes are cumulative and address previously issued AIX/VIOS BIND security bulletins with respect to SP and TL. The AIX and VIOS fixes can be downloaded via https from: https://www.ibm.com/resources/mrs/assets?source=aixbp IMPORTANT: If possible, it is recommended that a mksysb backup of the system be created. Verify it is both bootable and readable before proceeding. Note that all the previously reported security vulnerability fixes are also included in above mentioned fileset level. Please refer to the readme file (provided along with the fileset) for the complete list of vulnerabilities fixed. To preview the fix installation: installp -apYd . bind.rte To install the fix package: installp -aXYd . bind.rte To verify the advisory: 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_advisory24.asc.sig 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: ftp://ftp.software.ibm.com/systems/power/AIX/systems_p_os_aix_security_pubkey.txt 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_advisory24.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 (CVE-2023-2828) https://www.ibm.com/support/pages/node/7030969 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Thu Sep 7 13:08:07 CDT 2023 =============================================================================== *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.