IBM SECURITY ADVISORY First Issued: Fri Mar 4 09:00:01 CST 2022 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/pfcdd_advisory.asc https://aix.software.ibm.com/aix/efixes/security/pfcdd_advisory.asc ftp://aix.software.ibm.com/aix/efixes/security/pfcdd_advisory.asc Security Bulletin: Vulnerability in the AIX kernel (CVE-2021-38988) =============================================================================== SUMMARY: There is a vulnerability in the AIX pfcdd kernel extension. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2021-38988 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38988 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38988 DESCRIPTION: IBM AIX could allow a non-privileged local user to exploit a vulnerability in the AIX kernel to cause a denial of service. CVSS Base Score: 6.2 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/212950 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/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.pfcdd.rte 7.1.5.0 7.1.5.32 key_w_fs bos.pfcdd.rte 7.2.4.0 7.2.4.0 key_w_fs bos.pfcdd.rte 7.2.5.0 7.2.5.0 key_w_fs bos.pfcdd.rte 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.pfcdd.rte REMEDIATION: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY PRODUCT(S) ---------------------------------------------------------------- 7.1.5 IJ37508 ** SP10 key_w_apar base 7.2.4 IJ37504 ** SP06 key_w_apar base 7.2.5 IJ37494 ** SP04 key_w_apar base 7.3.0 IJ37403 ** SP02 key_w_apar base VIOS Level APAR Availability SP KEY PRODUCT(S) --------------------------------------------------------------- 3.1.1 IJ37504 ** 3.1.1.60 key_w_apar base 3.1.2 IJ37779 ** 3.1.2.40 key_w_apar base 3.1.3 IJ37494 ** 3.1.3.20 key_w_apar base Subscribe to the APARs here: http://www.ibm.com/support/pages/apar/IJ37403 http://www.ibm.com/support/pages/apar/IJ37494 http://www.ibm.com/support/pages/apar/IJ37504 http://www.ibm.com/support/pages/apar/IJ37508 http://www.ibm.com/support/pages/apar/IJ37779 https://www.ibm.com/support/pages/apar/IJ37403 https://www.ibm.com/support/pages/apar/IJ37494 https://www.ibm.com/support/pages/apar/IJ37504 https://www.ibm.com/support/pages/apar/IJ37508 https://www.ibm.com/support/pages/apar/IJ37779 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. An LPAR system reboot is required to complete the iFix installation, or Live Update may be used on AIX 7.2 and 7.3 to avoid a reboot. The AIX and VIOS fixes can be downloaded via ftp or http from: ftp://aix.software.ibm.com/aix/efixes/security/pfcdd_fix.tar http://aix.software.ibm.com/aix/efixes/security/pfcdd_fix.tar https://aix.software.ibm.com/aix/efixes/security/pfcdd_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 IJ37508s9a.220215.epkg.Z key_w_fix 7.1.5.8 IJ37508s9a.220215.epkg.Z key_w_fix 7.1.5.9 IJ37508s9a.220215.epkg.Z key_w_fix 7.2.4.3 IJ37504s5a.220215.epkg.Z key_w_fix 7.2.4.4 IJ37504s5a.220215.epkg.Z key_w_fix 7.2.4.5 IJ37504s5a.220215.epkg.Z key_w_fix 7.2.5.1 IJ37494s3a.220215.epkg.Z key_w_fix 7.2.5.2 IJ37494s3a.220215.epkg.Z key_w_fix 7.2.5.3 IJ37494s3a.220215.epkg.Z key_w_fix 7.3.0.1 IJ37403s1a.220215.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 IJ37504s5a.220215.epkg.Z key_w_fix 3.1.1.40 IJ37504s5a.220215.epkg.Z key_w_fix 3.1.1.50 IJ37504s5a.220215.epkg.Z key_w_fix 3.1.2.10 IJ37494s3a.220215.epkg.Z key_w_fix 3.1.2.21 IJ37494s3a.220215.epkg.Z key_w_fix 3.1.3.10 IJ37494s3a.220215.epkg.Z key_w_fix 3.1.3.14 IJ37494s3a.220215.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf pfcdd_fix.tar cd pfcdd_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 ----------------------------------------------------------------------------------------------------- 3b356bb54233c6ebabeacde2930b6323b8d80d0088cb445912b3b802383f3b68 IJ37403s1a.220215.epkg.Z key_w_csum b255d5f530a7901995cb365c8e95bd064f8384eb27396877fd7defd70e87635b IJ37494s3a.220215.epkg.Z key_w_csum 30f6523fde53aa9cdedc79649efc7cf169fd4fc624ec7d8b06a868a70865ff10 IJ37504s5a.220215.epkg.Z key_w_csum c49e1c3eb91495574a5980029a819629f178fa52f9dcaadaca20fa84fa281a8e IJ37508s9a.220215.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/pfcdd_advisory.asc.sig https://aix.software.ibm.com/aix/efixes/security/pfcdd_advisory.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/pfcdd_advisory.asc.sig C. FIX AND INTERIM FIX INSTALLATION An LPAR system reboot is required to complete the iFix installation, or Live Update may be used on AIX 7.2 to avoid a reboot. 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 the AIX kernel (CVE-2021-38988) https://www.ibm.com/support/pages/node/6561281 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Fri Mar 4 09:00:01 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.