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Security Bulletin: IBM i is vulnerable due to a flaw in Samba which could allow an attacker to bypass security restrictions (CVE-2023-4091)

Security Bulletin


Summary

Samba is available on IBM i to provide file system access. Samba could allow an attacker to bypass security restrictions due to a flaw as described in the vulnerability details section. IBM i has addressed the vulnerability in the Samba implementation by providing a fix as described in the remediation/fixes section.

Vulnerability Details

CVEID:   CVE-2023-4091
DESCRIPTION:   Samba could allow a remote authenticated attacker to bypass security restrictions, caused by a flaw when using the acl_xattr Samba VFS module with the smb.conf setting "acl_xattr:ignore system acls = yes". By sending a specially crafted request, an attacker could exploit this vulnerability to truncate files to 0 bytes.
CVSS Base score: 8.8
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/268588 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)

Affected Products and Versions

Affected Product(s)Version(s)
IBM i7.4
IBM i7.3
IBM i7.2

Remediation/Fixes

The issues can be fixed by applying a PTF to IBM i.  IBM i releases 7.4, 7.3, and 7.2 will be fixed.

The IBM i PTF number for 5770-SS1 contains the fix for the vulnerability.

 
IBM i Release5770-SS1PTF Download Link
7.4SI85145https://www.ibm.com/support/pages/ptf/SI85145
7.3SI85144https://www.ibm.com/support/pages/ptf/SI85144
7.2SI85143https://www.ibm.com/support/pages/ptf/SI85143

 

https://www.ibm.com/support/fixcentral

Important note: IBM recommends that all users running unsupported versions of affected products upgrade to supported and fixed version of affected products.

Workarounds and Mitigations

None

Get Notified about Future Security Bulletins

References

Off

Acknowledgement

Change History

09 Nov 2023: 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:
09 November 2023

UID

ibm17070196