IBM SECURITY ADVISORY First Issued: Thu Nov 7 15:49:20 CST 2024 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/tcl_advisory.asc Security Bulletin: AIX is vulnerable to arbitrary code execution (CVE-2023-36328) due to tcl =============================================================================== SUMMARY: Vulnerability in tcl could allow a remote attacker to execute arbitrary code or cause a denial of service (CVE-2023-36328). tcl is used by AIX =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2023-36328 https://www.cve.org/CVERecord?id=CVE-2023-36328 DESCRIPTION: libtom libtommath is vulnerable to an integer buffer overflow, caused by improper bounds checking by mp_grow. By sending a specially crafted request, a remote attacker could overflow a buffer and execute arbitrary code and cause a denial of service. CVSS Base Score: 9.8 CVSS Environmental Score*: Undefined CVSS Vector:(CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) AFFECTED PRODUCTS AND VERSIONS: AIX 7.2, 7.3 VIOS 3.1, 4.1 The following fileset levels are vulnerable: key_fileset = osrcaix Fileset Lower Level Upper Level KEY ------------------------------------------------------ tcl.base 8.6.10.0 8.6.10.0 key_w_fs To find out whether the affected filesets are installed on your systems, refer to the lslpp command found in the AIX user's guide. Example: lslpp -L | grep -i tcl.base REMEDIATION: A. FIXES IBM strongly recommends addressing the vulnerability now. The fixes can be downloaded via https from: https://aix.software.ibm.com/aix/efixes/security/tcl_fix.tar The links above are 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 Fix (*.Z) KEY ------------------------------------------- 7.2, 7.3 tcl-8.6.10.1.tar.Z key_w_fix VIOS Level Fix (*.Z) KEY ------------------------------------------- 3.1, 4.1 tcl-8.6.10.1.tar.Z key_w_fix To extract the fixes from the tar file: tar xvf tcl_fix.tar cd tcl_fix 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 ------------------------------------------------------------------------------------------------ d321324c1dea0878a984174bf7558c80b6d3af4b0c3ca12cc4980e5e291baee1 tcl-8.6.10.1.tar.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 AIX Support at https://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/tcl_advisory.asc.sig B. FIX AND INTERIM FIX INSTALLATION To extract the fixes from the tar file: zcat tcl-8.6.10.1.tar.Z | tar xvf - 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 . tcl To install the fix package: installp -aXYd . tcl 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/tcl_advisory.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: Review this information as needed, no action required. Complete CVSS v3 Guide: https://www.first.org/cvss/user-guide On-line Calculator v3: https://www.first.org/cvss/calculator/3.0 RELATED INFORMATION: Security Bulletin: AIX is vulnerable to arbitrary code execution (CVE-2023-36328) due to tcl https://www.ibm.com/support/pages/node/7175166 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Thu Nov 7 15:49:20 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.