IBM SECURITY ADVISORY First Issued: Mon Feb 28 16:34:28 CST 2022 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/audit_advisory.asc https://aix.software.ibm.com/aix/efixes/security/audit_advisory.asc ftp://aix.software.ibm.com/aix/efixes/security/audit_advisory.asc Security Bulletin: Vulnerability in AIX audit commands (CVE-2021-38955) =============================================================================== SUMMARY: There is a vulnerability in the AIX audit user commands. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2021-38955 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38955 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38955 DESCRIPTION: IBM AIX could allow a local user with elevated privileges to cause a denial of service due to a file creation vulnerability in the audit commands. CVSS Base Score: 4.4 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/211825 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/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 7.2.4.4 key_w_fs bos.rte.security 7.2.5.0 7.2.5.2 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 IJ38113 ** SP10 key_w_apar 7.2.4 IJ38115 ** SP06 key_w_apar 7.2.5 IJ38117 ** SP04 key_w_apar 7.3.0 IJ38121 ** SP02 key_w_apar VIOS Level APAR Availability SP KEY ---------------------------------------------------- 3.1.1 IJ38115 ** 3.1.1.60 key_w_apar 3.1.2 IJ38119 ** 3.1.2.40 key_w_apar 3.1.3 IJ38117 ** 3.1.3.20 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/pages/apar/IJ38113 http://www.ibm.com/support/pages/apar/IJ38115 http://www.ibm.com/support/pages/apar/IJ38117 http://www.ibm.com/support/pages/apar/IJ38119 http://www.ibm.com/support/pages/apar/IJ38121 https://www.ibm.com/support/pages/apar/IJ38113 https://www.ibm.com/support/pages/apar/IJ38115 https://www.ibm.com/support/pages/apar/IJ38117 https://www.ibm.com/support/pages/apar/IJ38119 https://www.ibm.com/support/pages/apar/IJ38121 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/audit_fix.tar http://aix.software.ibm.com/aix/efixes/security/audit_fix.tar https://aix.software.ibm.com/aix/efixes/security/audit_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 IJ38113m9a.220227.epkg.Z key_w_fix 7.1.5.8 IJ38113m9a.220227.epkg.Z key_w_fix 7.1.5.9 IJ38113m9a.220227.epkg.Z key_w_fix 7.2.4.3 IJ38115m5a.220227.epkg.Z key_w_fix 7.2.4.4 IJ38115m5a.220227.epkg.Z key_w_fix 7.2.4.5 IJ38115m5a.220227.epkg.Z key_w_fix 7.2.5.1 IJ38119m2a.220227.epkg.Z key_w_fix 7.2.5.2 IJ38119m2a.220227.epkg.Z key_w_fix 7.2.5.3 IJ38117m3a.220227.epkg.Z key_w_fix 7.3.0.1 IJ38121m1a.220227.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 ----------------------------------------------- 3.1.1.30 IJ38115m5a.220227.epkg.Z key_w_fix 3.1.1.40 IJ38115m5a.220227.epkg.Z key_w_fix 3.1.1.50 IJ38115m5a.220227.epkg.Z key_w_fix 3.1.2.10 IJ38119m2a.220227.epkg.Z key_w_fix 3.1.2.21 IJ38119m2a.220227.epkg.Z key_w_fix 3.1.3.10 IJ38117m3a.220227.epkg.Z key_w_fix 3.1.3.14 IJ38117m3a.220227.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf audit_fix.tar cd audit_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 ----------------------------------------------------------------------------------------------------- 9c106a0fcc85c04f1cb41b939b3019daa7fb2fa2b826f6ea41bf4b6e415f54ae IJ38113m9a.220227.epkg.Z key_w_csum 3da452a1fadea25122c899a851907b8df6e0346f016373e22e98a36a7deedaf2 IJ38115m5a.220227.epkg.Z key_w_csum abcc517295ba08a79f994f1091778c7845729cb96a0ac5530b0777ea23e93050 IJ38117m3a.220227.epkg.Z key_w_csum 851e4b2c602e5e869b36bea8190da813b880f10aae6227f2595ecf06289dd58c IJ38119m2a.220227.epkg.Z key_w_csum e61fce4c31be526987ad5842155d71a8912622dde0b76091545ad3a40ea70f78 IJ38121m1a.220227.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/audit_advisory.asc.sig https://aix.software.ibm.com/aix/efixes/security/audit_advisory.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/audit_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 AIX audit commands (CVE-2021-38955) https://www.ibm.com/support/pages/node/6560236 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Mon Feb 28 16:34:28 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.