IBM SECURITY ADVISORY First Issued: Tue Jul 25 11:08:32 CDT 2023 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory5.asc Security Bulletin: AIX is vulnerable to a denial of service due to libxml2 (CVE-2023-29469 and CVE-2023-28484) =============================================================================== SUMMARY: Vulnerabilities in libxml2 could allow a remote attacker to cause a denial of service (CVE-2023-29469 and CVE-2023-28484). AIX uses libxml2 as part of its XML parsing functions. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2023-29469 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-29469 DESCRIPTION: GNOME libxml2 is vulnerable to a denial of service, caused by a double free flaw in the xmlDictComputeFastKey function due to hashing empty strings are not null-terminated. By persuading a victim to open a specially crafted XML content, a remote attacker could exploit this vulnerability to cause a denial of service condition. CVSS Base Score: 5.5 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/253143 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) CVEID: CVE-2023-28484 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-28484 DESCRIPTION: GNOME libxml2 is vulnerable to a denial of service, caused by a NULL pointer dereference flaw in the xmlSchemaFixupComplexType function. By persuading a victim to open a specially crafted XML content, a remote attacker could exploit this vulnerability to cause a denial of service condition. CVSS Base Score: 5.5 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/253138 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/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 --------------------------------------------------------- bos.rte.control 7.2.5.0 7.2.5.6 key_w_fs bos.rte.control 7.2.5.100 7.2.5.103 key_w_fs bos.rte.control 7.2.5.200 7.2.5.201 key_w_fs bos.rte.control 7.3.0.0 7.3.0.3 key_w_fs bos.rte.control 7.3.1.0 7.3.1.1 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 bos.rte.control REMEDIATION: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY ----------------------------------------------------- 7.2.5 IJ47597 ** SP07 key_w_apar 7.3.0 IJ47629 ** N/A key_w_apar 7.3.1 IJ47630 ** SP03 key_w_apar VIOS Level APAR Availability SP KEY ----------------------------------------------------- 3.1.2 IJ47631 ** N/A key_w_apar 3.1.3 IJ47632 ** 3.1.3.50 key_w_apar 3.1.4 IJ47597 ** 3.1.4.30 key_w_apar Subscribe to the APARs here: https://www.ibm.com/support/pages/apar/IJ47597 https://www.ibm.com/support/pages/apar/IJ47629 https://www.ibm.com/support/pages/apar/IJ47630 https://www.ibm.com/support/pages/apar/IJ47631 https://www.ibm.com/support/pages/apar/IJ47632 By subscribing, you will receive periodic email alerting you to the status of the APAR, and a link to download the fix once it becomes available. B. FIXES IBM strongly recommends addressing the vulnerability now. AIX and VIOS fixes are available. The fixes are cumulative and address previously issued AIX/VIOS libxml2 security bulletins with respect to SP and TL: https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory4.asc https://www.ibm.com/support/pages/node/6953825 https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc https://www.ibm.com/support/pages/node/6619729 The AIX and VIOS fixes can be downloaded via ftp or http from: https://aix.software.ibm.com/aix/efixes/security/libxml2_fix5.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 AIX Technology Levels. AIX Level Interim Fix (*.Z) KEY ---------------------------------------------- 7.2.5.4 IJ47597m4a.230718.epkg.Z key_w_fix 7.2.5.5 IJ47597m6a.230717.epkg.Z key_w_fix 7.2.5.6 IJ47597m6a.230717.epkg.Z key_w_fix 7.3.0.2 IJ47629m4a.230718.epkg.Z key_w_fix 7.3.0.3 IJ47629m4a.230718.epkg.Z key_w_fix 7.3.0.4 IJ47629m4a.230718.epkg.Z key_w_fix 7.3.1.1 IJ47630m2a.230718.epkg.Z key_w_fix 7.3.1.2 IJ47630m2a.230718.epkg.Z key_w_fix Please note that the above table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.3.0.3 is AIX 7300-00-03. Please reference the Affected Products and Version section above for help with checking installed fileset levels. VIOS Level Interim Fix (*.Z) KEY ----------------------------------------------- 3.1.2.40 IJ47631m6a.230718.epkg.Z key_w_fix 3.1.2.50 IJ47631m6a.230718.epkg.Z key_w_fix 3.1.2.60 IJ47631m6a.230718.epkg.Z key_w_fix 3.1.3.21 IJ47632m4a.230718.epkg.Z key_w_fix 3.1.3.30 IJ47632m4a.230718.epkg.Z key_w_fix 3.1.3.40 IJ47632m4a.230718.epkg.Z key_w_fix 3.1.4.10 IJ47597m6a.230717.epkg.Z key_w_fix 3.1.4.21 IJ47597m6a.230717.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf libxml2_fix5.tar cd libxml2_fix5 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 ----------------------------------------------------------------------------------------------------- 3d2d1242eb42fadb11d1c3e9625a81bdf3f605a465039b7592d46ab401e68af7 IJ47597m4a.230718.epkg.Z key_w_csum c06c96eeae459c2533b0d2df958f31aafbcc6c274a732324039328ee7a272f97 IJ47597m6a.230717.epkg.Z key_w_csum b80ac199295a15227b8e946ff5db42324e62e40bbfbb59d81f5b2627286e505b IJ47629m4a.230718.epkg.Z key_w_csum 85b4de5a3bd7098cb808f48a9ceb40f3aefddae418e902f42691f68882d850c8 IJ47630m2a.230718.epkg.Z key_w_csum a72eb5c8c9012a0a3d9b4789b257e29740720f4a1948c2971d6dafd77ecccadc IJ47631m6a.230718.epkg.Z key_w_csum 38539a5de0ac8961a32bb5e872a79d4bee66b5de6735c9f049f2decc6dac581c IJ47632m4a.230718.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/libxml2_advisory5.asc.sig C. 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: http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html 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: 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/libxml2_advisory5.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 a denial of service due to libxml2 (CVE-2023-29469 and CVE-2023-28484) https://www.ibm.com/support/pages/node/7014485 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Tue Jul 25 11:08:32 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.