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

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

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.

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