IBM SECURITY ADVISORY First Issued: Mon Jan 10 13:18:02 CST 2022 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/lscore_advisory.asc https://aix.software.ibm.com/aix/efixes/security/lscore_advisory.asc ftp://aix.software.ibm.com/aix/efixes/security/lscore_advisory.asc Security Bulletin: Vulnerability in lscore affects AIX (CVE-2021-38991) =============================================================================== SUMMARY: There is a vulnerability in the lscore command that affects AIX. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2021-38991 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38991 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38991 DESCRIPTION: IBM AIX could allow a non-privileged local user to exploit a vulnerability in the lscore command which could lead to code execution. CVSS Base Score: 8.4 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/212953 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) AFFECTED PRODUCTS AND VERSIONS: AIX 7.1, 7.2, 7.3 VIOS 3.1 The vulnerabilities in the following filesets are being addressed: key_fileset = aix Fileset Lower Level Upper Level KEY --------------------------------------------------------- bos.rte.security 7.1.5.0 7.1.5.37 key_w_fs bos.rte.security 7.2.4.0 7.2.4.3 key_w_fs bos.rte.security 7.2.5.0 7.2.5.1 key_w_fs bos.rte.security 7.2.5.100 7.2.5.101 key_w_fs bos.rte.security 7.3.0.0 7.3.0.0 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.security REMEDIATION: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY ----------------------------------------------------- 7.1.5 IJ36805 ** SP10 key_w_apar 7.2.4 IJ36806 ** SP06 key_w_apar 7.2.5 IJ36810 ** SP04 key_w_apar 7.3.0 IJ36816 ** SP02 key_w_apar VIOS Level APAR Availability SP KEY ---------------------------------------------------- 3.1.1 IJ36806 ** 3.1.1.60 key_w_apar 3.1.2 IJ36815 ** 3.1.2.40 key_w_apar 3.1.3 IJ36810 ** 3.1.3.20 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/pages/apar/IJ36805 http://www.ibm.com/support/pages/apar/IJ36806 http://www.ibm.com/support/pages/apar/IJ36810 http://www.ibm.com/support/pages/apar/IJ36815 http://www.ibm.com/support/pages/apar/IJ36816 https://www.ibm.com/support/pages/apar/IJ36805 https://www.ibm.com/support/pages/apar/IJ36806 https://www.ibm.com/support/pages/apar/IJ36810 https://www.ibm.com/support/pages/apar/IJ36815 https://www.ibm.com/support/pages/apar/IJ36816 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 AIX and VIOS fixes are available. The AIX and VIOS fixes can be downloaded via ftp or http from: ftp://aix.software.ibm.com/aix/efixes/security/lscore_fix.tar http://aix.software.ibm.com/aix/efixes/security/lscore_fix.tar https://aix.software.ibm.com/aix/efixes/security/lscore_fix.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 ---------------------------------------------- 7.1.5.7 IJ36805s9a.211217.epkg.Z key_w_fix 7.1.5.8 IJ36805s9a.211217.epkg.Z key_w_fix 7.1.5.9 IJ36805s9a.211217.epkg.Z key_w_fix 7.2.4.2 IJ36806s2a.211217.epkg.Z key_w_fix 7.2.4.3 IJ36806s4a.211217.epkg.Z key_w_fix 7.2.4.4 IJ36806s4a.211217.epkg.Z key_w_fix 7.2.5.1 IJ36815s2a.211217.epkg.Z key_w_fix 7.2.5.2 IJ36815s2a.211217.epkg.Z key_w_fix 7.2.5.3 IJ36810s3a.211217.epkg.Z key_w_fix 7.3.0.1 IJ36816s1a.211217.epkg.Z key_w_fix Please note that the above table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.2.5.2 is AIX 7200-05-02. Please reference the Affected Products and Version section above for help with checking installed fileset levels. VIOS Level Interim Fix (*.Z) KEY ----------------------------------------------- 3.1.1.21 IJ36806s2a.211217.epkg.Z key_w_fix 3.1.1.25 IJ36806s2a.211217.epkg.Z key_w_fix 3.1.1.30 IJ36806s4a.211217.epkg.Z key_w_fix 3.1.1.40 IJ36806s4a.211217.epkg.Z key_w_fix 3.1.2.10 IJ36815s2a.211217.epkg.Z key_w_fix 3.1.2.21 IJ36815s2a.211217.epkg.Z key_w_fix 3.1.3.10 IJ36810s3a.211217.epkg.Z key_w_fix 3.1.3.14 IJ36810s3a.211217.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf lscore_fix.tar cd lscore_fix 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 ----------------------------------------------------------------------------------------------------- 866141e4fcc92ecbfff15e3c216347f8788a84bba558647b53256acdf338c4dd IJ36805s9a.211217.epkg.Z key_w_csum 8be118a07a65509c99d09c7cd0b8e55f9eb192a0ceff7f73beb973031f405515 IJ36806s2a.211217.epkg.Z key_w_csum 870448503c15caabb138e93d4d7e32348af51f8ef4db0cf35047876a5da0f68a IJ36806s4a.211217.epkg.Z key_w_csum c8cf7f12d62220e44d22360cfc408bb6e3d090c3401429cddb4a4bf1e6c5160e IJ36810s3a.211217.epkg.Z key_w_csum 428938e255b869354fbd4e43f007b4e7224cdeb43d9ec1cc7cfecbfb18a244cc IJ36815s2a.211217.epkg.Z key_w_csum eb681a0a23855b1805b6d5d111f5bb50faf318221b29e9af016ae3d410d9efa8 IJ36816s1a.211217.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: http://aix.software.ibm.com/aix/efixes/security/lscore_advisory.asc.sig https://aix.software.ibm.com/aix/efixes/security/lscore_advisory.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/lscore_advisory.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 To view previously issued advisories, please visit: http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq Contact IBM Support for questions related to this announcement: http://ibm.com/support/ https://ibm.com/support/ 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 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: Vulnerability in lscore affects AIX (CVE-2021-38991) https://www.ibm.com/support/pages/node/6538952 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Mon Jan 10 13:18:02 CST 2022 =============================================================================== *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.