IBM SECURITY ADVISORY First Issued: Wed Apr 12 12:36:51 CDT 2023 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/librts_advisory.asc Security Bulletin: AIX is vulnerable to arbitrary command execution (CVE-2023-26286) =============================================================================== SUMMARY: A vulnerability in the AIX runtime services library could allow a non-privileged local user to execute arbitrary commands (CVE-2023-26286). =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2023-26286 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-26286 DESCRIPTION: IBM AIX could allow a non-privileged local user to exploit a vulnerability in the AIX runtime services library to execute arbitrary commands. CVSS Base Score: 8.4 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/248421 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.mp64 7.1.5.0 7.1.5.47 key_w_fs bos.rte.serv_aid 7.1.5.0 7.1.5.36 key_w_fs bos.mp64 7.2.5.0 7.2.5.6 key_w_fs bos.rte.serv_aid 7.2.5.0 7.2.5.4 key_w_fs bos.sysmgt.serv_aid 7.2.5.0 7.2.5.3 key_w_fs bos.mp64 7.2.5.100 7.2.5.106 key_w_fs bos.rte.serv_aid 7.2.5.100 7.2.5.102 key_w_fs bos.sysmgt.serv_aid 7.2.5.100 7.2.5.102 key_w_fs bos.mp64 7.2.5.200 7.2.5.201 key_w_fs bos.rte.serv_aid 7.2.5.200 7.2.5.200 key_w_fs bos.sysmgt.serv_aid 7.2.5.200 7.2.5.200 key_w_fs bos.mp64 7.3.0.0 7.3.0.4 key_w_fs bos.rte.serv_aid 7.3.0.0 7.3.0.2 key_w_fs bos.sysmgt.serv_aid 7.3.0.0 7.3.0.1 key_w_fs bos.mp64 7.3.1.0 7.3.1.1 key_w_fs bos.rte.serv_aid 7.3.1.0 7.3.1.1 key_w_fs bos.sysmgt.serv_aid 7.3.1.0 7.3.1.0 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.mp64 REMEDIATION: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY ----------------------------------------------------- 7.1.5 IJ45981 ** SP12 key_w_apar 7.2.5 IJ45245 ** SP06 key_w_apar 7.3.0 IJ45997 ** SP04 key_w_apar 7.3.1 IJ45246 ** SP02 key_w_apar VIOS Level APAR Availability SP KEY ----------------------------------------------------- 3.1.2 IJ46110 ** 3.1.2.60 key_w_apar 3.1.3 IJ46051 ** 3.1.3.40 key_w_apar 3.1.4 IJ45245 ** 3.1.4.20 key_w_apar Subscribe to the APARs here: https://www.ibm.com/support/pages/apar/[APAR Number] 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 AIX and VIOS fixes can be downloaded via https from: https://aix.software.ibm.com/aix/efixes/security/librts_fix.tar The AIX error daemon, errdemon, should be stopped and restarted after iFix installation to complete the install: # /usr/lib/errstop # /usr/lib/errdemon 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 ---------------------------------------------- 7.1.5.9 IJ45981s9a.230324.epkg.Z key_w_fix 7.1.5.10 IJ45981sAa.230323.epkg.Z key_w_fix 7.1.5.11 IJ45981sBa.230407.epkg.Z key_w_fix 7.2.5.3 IJ45245s3a.230324.epkg.Z key_w_fix 7.2.5.4 IJ45245s4a.230324.epkg.Z key_w_fix 7.2.5.5 IJ45245s5a.230322.epkg.Z key_w_fix 7.3.0.1 IJ45997s1a.230322.epkg.Z key_w_fix 7.3.0.2 IJ45997s2a.230322.epkg.Z key_w_fix 7.3.0.3 IJ45997s3a.230322.epkg.Z key_w_fix 7.3.1.1 IJ45246s1a.230322.epkg.Z key_w_fix Please note that the above table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.2.5.4 is AIX 7200-05-04. VIOS Level Interim Fix (*.Z) KEY -------------------------------------------- 3.1.2.30 IJ46110s3a.230323.epkg.Z key_w_fix 3.1.2.40 IJ46110s4a.230323.epkg.Z key_w_fix 3.1.2.50 IJ46110s5a.230407.epkg.Z key_w_fix 3.1.3.14 IJ46051s1a.230323.epkg.Z key_w_fix 3.1.3.21 IJ46051s2a.230323.epkg.Z key_w_fix 3.1.3.30 IJ46051s3a.230323.epkg.Z key_w_fix 3.1.4.10 IJ45245s5a.230322.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf librts_fix.tar cd librts_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 ----------------------------------------------------------------------------------------------------- b2ce7cf6aed5e9e325a9babf29e950f5d0aef394da305e32ad54bd8af13a04f8 IJ45245s3a.230324.epkg.Z key_w_csum f1729e6086bdab6669cd45841707cb398acbf0acbacc351ac7e5ad67260ee713 IJ45245s4a.230324.epkg.Z key_w_csum 60fe19af30c5e32f7a129b82cbcab606cd08236e73c0dcd968b5ab495fdd2476 IJ45245s5a.230322.epkg.Z key_w_csum 016fcc1f02f1690d38d4558b4d9457271d2fc97320ead6e9af2164c1036ff5a9 IJ45246s1a.230322.epkg.Z key_w_csum c0fae4d17e285bf82780de8dde66b98f92d41d3b3e556888dd3f45e46d33b96b IJ45981sAa.230323.epkg.Z key_w_csum c789fbd38fb99cc00c67dad1593d7db9d6e9442be366e1a7b7052551d58e88b1 IJ45981sBa.230407.epkg.Z key_w_csum 8d065f161451d2c4610cfc9efc2784e6bba7f4d2edb6687d31fd1a46b8358a40 IJ45981s9a.230324.epkg.Z key_w_csum 5f51f7577ef77d0e67d06da73992c8b425d369de935c54c87e10ad57b7d0c8d9 IJ45997s1a.230322.epkg.Z key_w_csum 24f05177f32ef54b38eb0649cfc51a64e3c548b69382dbe35fea8ffa7ce7f291 IJ45997s2a.230322.epkg.Z key_w_csum a3df21e1d61dfa3763cb5961e202aedd4b57506afd13a5e089f77cfb6f4cc83c IJ45997s3a.230322.epkg.Z key_w_csum 7de35cba53f8f092c6aeeb545dad69dbea85855044480205c0eb1298065e013e IJ46051s1a.230323.epkg.Z key_w_csum 356e002d20e36ddc4814ebb1517826eafca3cfab3434f4d47892665a21d7da5a IJ46051s2a.230323.epkg.Z key_w_csum 5673b7e749d7bada523a2d3917fe03a3cb69025ebb10c8080be8f53a7b8db761 IJ46051s3a.230323.epkg.Z key_w_csum e3465d874ddfbb283c4a4985f77f7f777beb63a273d3704f9fb663a94f1ae1e1 IJ46110s3a.230323.epkg.Z key_w_csum 2badfd45477c32a71378f3e61f0b887ae19a50e588e6a18b9c5c99694af09b9c IJ46110s4a.230323.epkg.Z key_w_csum f36c500647ce64a4ed9b5ad2bde3c09db4f98007781921982b84cde7551a2d8b IJ46110s5a.230407.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/librts_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 Contact IBM Support for questions related to this announcement: 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: AIX is vulnerable to arbitrary command execution (CVE-2023-26286) https://www.ibm.com/support/pages/node/6983236 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Wed Apr 12 12:36:51 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.