IBM SECURITY ADVISORY First Issued: Thu Jan 6 09:30:39 CST 2022 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/mount_advisory.asc https://aix.software.ibm.com/aix/efixes/security/mount_advisory.asc ftp://aix.software.ibm.com/aix/efixes/security/mount_advisory.asc Security Bulletin: Vulnerability in mount affects AIX (CVE-2021-38990) =============================================================================== SUMMARY: There is a vulnerability in the mount command that affects AIX. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2021-38990 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38990 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38990 DESCRIPTION: IBM AIX could allow a non-privileged local user to exploit a vulnerability in the mount command which could lead to code execution. CVSS Base Score: 8.4 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/212952 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 VIOS 3.1 The vulnerabilities in the following filesets are being addressed: key_fileset = aix Fileset Lower Level Upper Level KEY --------------------------------------------------------- bos.rte.filesystem 7.1.5.0 7.1.5.36 key_w_fs bos.rte.filesystem 7.2.4.0 7.2.4.2 key_w_fs bos.rte.filesystem 7.2.5.0 7.2.5.1 key_w_fs bos.rte.filesystem 7.2.5.100 7.2.5.100 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.filesystem REMEDIATION: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY ----------------------------------------------------- 7.1.5 IJ35620 ** SP09-2148 key_w_apar 7.2.4 IJ35826 ** SP05 key_w_apar 7.2.5 IJ35623 ** SP03-2147 key_w_apar VIOS Level APAR Availability SP KEY ---------------------------------------------------- 3.1.1 IJ35826 ** 3.1.1.50 key_w_apar 3.1.2 IJ36125 ** 3.1.2.30 key_w_apar 3.1.3 IJ35623 ** 3.1.3.13 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/pages/apar/IJ35620 http://www.ibm.com/support/pages/apar/IJ35623 http://www.ibm.com/support/pages/apar/IJ35826 http://www.ibm.com/support/pages/apar/IJ36125 https://www.ibm.com/support/pages/apar/IJ35620 https://www.ibm.com/support/pages/apar/IJ35623 https://www.ibm.com/support/pages/apar/IJ35826 https://www.ibm.com/support/pages/apar/IJ36125 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/mount_fix.tar http://aix.software.ibm.com/aix/efixes/security/mount_fix.tar https://aix.software.ibm.com/aix/efixes/security/mount_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 IJ35620s9a.211130.epkg.Z key_w_fix 7.1.5.8 IJ35620s9a.211130.epkg.Z key_w_fix 7.1.5.9 IJ35620s9a.211130.epkg.Z key_w_fix 7.2.4.2 IJ35826s2a.211130.epkg.Z key_w_fix 7.2.4.3 IJ35826s4a.211130.epkg.Z key_w_fix 7.2.4.4 IJ35826s4a.211130.epkg.Z key_w_fix 7.2.5.1 IJ36125s2a.211130.epkg.Z key_w_fix 7.2.5.2 IJ36125s2a.211130.epkg.Z key_w_fix 7.2.5.3 IJ35623s3a.211130.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 IJ35826s2a.211130.epkg.Z key_w_fix 3.1.1.25 IJ35826s2a.211130.epkg.Z key_w_fix 3.1.1.30 IJ35826s4a.211130.epkg.Z key_w_fix 3.1.1.40 IJ35826s4a.211130.epkg.Z key_w_fix 3.1.2.10 IJ36125s2a.211130.epkg.Z key_w_fix 3.1.2.21 IJ36125s2a.211130.epkg.Z key_w_fix 3.1.3.10 IJ35623s3a.211130.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf mount_fix.tar cd mount_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 ----------------------------------------------------------------------------------------------------- 08c0bfe458bf5d36a4dfb1841e9b35be6e3c216f38c537d528e16cf2b68239d2 IJ35620s9a.211130.epkg.Z key_w_csum 52c67adcfdb606dc757bcf40df439fef0dca37bb36e25c3b474fc7f3e80bb93c IJ35623s3a.211130.epkg.Z key_w_csum 5f7cfdb4181030b7bf42a8512bba399ed67f54203672a42b43dc61813743796f IJ35826s2a.211130.epkg.Z key_w_csum 178b67c1979a2b9240e727bf737017157ba2a2dd0f3da5568646540efcbaf9b7 IJ35826s4a.211130.epkg.Z key_w_csum 2ce1eceacfc430e6b37ebdc3a999b77e83b907847978bba15cdcbb31d68897dd IJ36125s2a.211130.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/mount_advisory.asc.sig https://aix.software.ibm.com/aix/efixes/security/mount_advisory.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/mount_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 mount affects AIX (CVE-2021-38990) https://www.ibm.com/support/pages/node/6538700 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Thu Jan 6 09:30:39 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.