IBM SECURITY ADVISORY First Issued: Wed Apr 12 12:32:10 CDT 2023 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/invscout_advisory4.asc Security Bulletin: AIX is vulnerable to arbitrary command execution due to invscout (CVE-2023-28528) =============================================================================== SUMMARY: A vulnerability in the AIX invscout command could allow a non-privileged local user to execute arbitrary commands (CVE-2023-28528). =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2023-28528 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-28528 DESCRIPTION: IBM AIX could allow a non-privileged local user to exploit a vulnerability in the invscout command to execute arbitrary commands. CVSS Base Score: 8.4 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/251207 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 following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY --------------------------------------------------------- invscout.rte 2.2.0.0 2.2.0.23 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 invscout.rte REMEDIATION: A. 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/invscout_fix4.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. For AIX 7.1, 7.2, and VIOS 3.1, you must be on the 'bos.rte.libc prereq' level before installing the new invscout.rte package. AIX Level bos.rte.libc prereq ---------------------------------- 7.1 7.1.5.30 7.2 7.2.3.0 VIOS Level bos.rte.libc prereq ---------------------------------- 3.1 7.2.3.0 To extract the fixes from the tar file: tar xvf invscout_fix4.tar cd invscout_fix4 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 ----------------------------------------------------------------------------------------------------- f13845513b60d3df0699a30fa1c328079983a35ae4b6cfa6db4e4d571b2d530c invscout.rte 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/invscout_advisory4.asc.sig B. 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 the fix installation: installp -apYd . invscout To install the fix package: installp -aXYd . invscout 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 due to invscout (CVE-2023-28528) https://www.ibm.com/support/pages/node/6983232 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Wed Apr 12 12:32:10 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.