IBM SECURITY ADVISORY First Issued: Tue Jun 10 08:33:35 CDT 2025 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/openssh_advisory19.asc Security Bulletin: AIX is vulnerable to an expected behavior violation (CVE-2025-32728) due to OpenSSH =============================================================================== SUMMARY: AIX's OpenSSH DisableForwarding directive does not adhere to the documentation (CVE-2025-32728). OpenSSH is used by AIX for remote login. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2025-32728 https://www.cve.org/CVERecord?id=CVE-2025-32728 DESCRIPTION: In sshd in OpenSSH before 10.0, the DisableForwarding directive does not adhere to the documentation stating that it disables X11 and agent forwarding. CVSS Base Score: 3.8 CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N) AFFECTED PRODUCTS AND VERSIONS: AIX 7.2, 7.3 VIOS 3.1, 4.1 The following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY --------------------------------------------------------------- openssh.base.client 9.2.112.0 9.7.3013.1000 key_w_fs openssh.base.server 9.2.112.0 9.7.3013.1000 key_w_fs openssh.base.client 9.9.3015.1000 9.9.3015.1000 key_w_fs openssh.base.server 9.9.3015.1000 9.9.3015.1000 key_w_fs Note: A. OpenSSH versions below 9.7 are out-of-support. Customers are advised to update to the latest OpenSSH version from the Web Download site: https://www.ibm.com/resources/mrs/assets?source=aixbp 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 openssh.base.client 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/openssh_fix19.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. Note that the tar file contains Interim fixes that are based on OpenSSH version, and AIX OpenSSH fixes are cumulative. You must be on the 'prereq for installation' level before applying the interim fix. This may require installing a new level(prereq version) first from: https://www.ibm.com/resources/mrs/assets?source=aixbp AIX Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY --------------------------------------------------------------------------------------- 7.2, 7.3 3272897ma.250521.epkg.Z openssh.base(9.7.3013.1000) key_w_fix 7.2, 7.3 3272899ma.250521.epkg.Z openssh.base(9.9.3015.1000) key_w_fix VIOS Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY -------------------------------------------------------------------------------------------- 3.1, 4.1 3272897ma.250521.epkg.Z openssh.base(9.7.3013.1000) key_w_fix 3.1, 4.1 3272899ma.250521.epkg.Z openssh.base(9.9.3015.1000) key_w_fix To extract the fixes from the tar file: tar xvf openssh_fix19.tar cd openssh_fix19 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 ----------------------------------------------------------------------------------------------------- 2710f8a132bd61754d9dceca8b2757ba2ee25fab3b8ca8c84f2bd06ff1e77942 3272897ma.250521.epkg.Z key_w_csum 2822b9994a867cf1ffa0158a669bb90eb1a6cf600877b54d89f754ccc02b5177 3272899ma.250521.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/openssh_advisory19.asc.sig B. 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: https://www.ibm.com/support/pages/managing-interim-fixes-aix 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/ For information on how to securely verify AIX security bulletins and fixes: https://www.ibm.com/support/pages/node/6985269 To obtain the OpenSSL public key that can be used to verify the signed advisories and ifixes: Download the key from our web page: https://aix.software.ibm.com/aix/efixes/security/systems_p_os_aix_security_pubkey.txt To verify the AIX/VIOS security bulletin: Published advisory OpenSSL signature file location: https://aix.software.ibm.com/aix/efixes/security/openssh_advisory19.asc.sig openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file] Please contact your local IBM AIX support center for any assistance. REFERENCES: Complete CVSS v3 Guide: https://www.first.org/cvss/user-guide On-line Calculator v3: https://www.first.org/cvss/calculator/3.0 RELATED INFORMATION: IBM Secure Engineering Web Portal https://www.ibm.com/support/pages/ibm-security-vulnerability-management IBM Product Security Incident Response Blog https://www.ibm.com/blogs/psirt/ Security Bulletin: AIX is vulnerable to an expected behavior violation (CVE-2025-32728) due to OpenSSH https://www.ibm.com/support/pages/node/7236104 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Tue Jun 10 08:33:35 CDT 2025 =============================================================================== *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.