IBM SECURITY ADVISORY First Issued: Wed Feb 21 15:59:59 CST 2024 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/perl_advisory8.asc Security Bulletin: AIX is vulnerable to arbitrary command execution due to Perl (CVE-2024-25021, CVE-2023-47038, CVE-2023-47100) =============================================================================== SUMMARY: Vulnerabilities in AIX's Perl could allow an attacker to execute arbitrary commands (CVE-2024-25021, CVE-2023-47038, CVE-2023-47100) AIX uses Perl in various operating system components. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2024-25021 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-25021 DESCRIPTION: IBM AIX's Perl implementation could allow a non-privileged local user to exploit a vulnerability to execute arbitrary commands. CVSS Base Score: 8.4 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/281320 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) CVEID: CVE-2023-47038 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-47038 DESCRIPTION: Perl is vulnerable to a heap-based buffer overflow, caused by improper bounds checking by the user-defined Unicode property. By persuading a victim to use specially crafted regular expression to compile, a remote attacker could overflow a buffer and execute arbitrary code on the system. CVSS Base Score: 7.8 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/272814 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) CVEID: CVE-2023-47100 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-47100 DESCRIPTION: Perl could allow a remote attacker to bypass security restrictions, caused by improper handling of property name by the S_parse_uniprop_string function in regcomp.c. By using a specially crafted regular expression input, an attacker could exploit this vulnerability to write to unallocated space. CVSS Base Score: 9.8 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/272992 for the current score 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 7.3 VIOS 4.1 The following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY --------------------------------------------------------- perl.rte 5.34.0.0 5.34.1.5 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 perl.rte REMEDIATION: A. FIXES IBM strongly recommends addressing the vulnerability now. AIX and VIOS fileset updates are available. The AIX and VIOS fileset update can be downloaded via https from, under 'Perl - Perl Version 5 Runtime': https://www.ibm.com/resources/mrs/assets?source=aixbp For AIX 7.3 TL1 and above, and for VIOS 4.1: perl.rte.5.34.1.6 The fileset update has a dependency on OpenSSL 3.0. Alternatively, AIX and VIOS fixes are also available. The AIX and VIOS fixes can be downloaded via https from: https://aix.software.ibm.com/aix/efixes/security/perl_fix8.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 Perl fileset levels. AIX Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY --------------------------------------------------------------------------------------- 7.3.1, 7.3.2 perl5345ma.240213.epkg.Z perl.rte(5.34.1.2) key_w_fix VIOS Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY --------------------------------------------------------------------------------------- 4.1 perl5345ma.240213.epkg.Z perl.rte(5.34.1.2) key_w_fix To extract the fixes from the tar file: tar xvf perl_fix8.tar cd perl_fix8 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 ----------------------------------------------------------------------------------------------------- 3429696297740123a42cd1957c54caa8a72e398252e063836579adc29863e031 perl5345ma.240213.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: https://aix.software.ibm.com/aix/efixes/security/perl_advisory8.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 the fileset installation: installp -apYd . perl To install the fileset update: installp -aXYd . perl 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": http://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/perl_advisory8.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 arbitrary command execution due to Perl (CVE-2024-25021, CVE-2023-47038, CVE-2023-47100) https://www.ibm.com/support/pages/node/7122628 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Wed Feb 21 15:59:59 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.