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Security Bulletin: IBM i Access Client Solutions is vulnerable to remote credential theft when NTLM is enabled on Windows workstations

Security Bulletin


Summary

IBM i Access Client Solutions (ACS) is vulnerable to remote credential theft when NT LAN Manager (NTLM) is enabled on Windows workstations (CVE-2024-22318). Since IBM i Access Client solutions allows Universal Naming Convention (UNC) paths in its configuration files, if a path is modified to point to a hostile server, the NTLM hash can be harvested during the NTLM authentication and used for an additional attack.

Vulnerability Details

CVEID:   CVE-2024-22318
DESCRIPTION:   IBM i Access Client Solutions (ACS) is vulnerable to NT LAN Manager (NTLM) hash disclosure by an attacker modifying UNC capable paths within ACS configuration files to point to a hostile server. If NTLM is enabled, the Windows operating system will try to authenticate using the current user's session. The hostile server could capture the NTLM hash information to obtain the user's credentials.
CVSS Base score: 5.1
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/279091 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N)

Affected Products and Versions

Affected Product(s)Version(s)
IBM i Access Family1.1.2 - 1.1.4,
1.1.4.3 - 1.1.9.4

Remediation/Fixes

None

Workarounds and Mitigations

NT LAN Manager (NTLM) is not used directly by IBM i Access Client Solutions (ACS), nor does ACS have any specific support for it. Since ACS does not prevent the usage of Universal Naming Convention (UNC) paths, when a UNC path is encountered while using ACS, NTLM authentication could be performed by the Windows operating system.  Administrators and users need to be aware that if NTLM is enabled on a Windows workstation it is vulnerable to a variety of NTLM security issues.

IBM recommends not using NT LAN Manager (NTLM).  For information on restricting NTLM, see section 11.1.4 Restricting Windows NTLM in the GettingStarted document for IBM i Access Client Solutions with a publish date of January 24, 2024 or later.

Please note: Users of future releases of IBM i Access family of products should be directed to follow this same guidance.

Get Notified about Future Security Bulletins

References

Off

Acknowledgement

The vulnerability was reported to IBM by John Page (aka hyp3rlinx) / https://twitter.com/hyp3rlinx

Change History

07 Feb 2024: Initial Publication

*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. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.

Document Location

Worldwide

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Document Information

Modified date:
08 February 2024

UID

ibm17116091