Vulnerability identifier: #VU81872

Vulnerability risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-4091

CWE-ID: CWE-264

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Samba
Server applications / Directory software, identity management

Vendor: Samba

Description

The vulnerability allows a remote user to truncate read-only files.

The vulnerability exists due to an error in the way SMB protocol implementation in Samba handles file operations. A remote user can request read-only access to files and then truncate them to 0 bytes by opening files with OVERWRITE disposition when using the acl_xattr Samba VFS module with the smb.conf setting "acl_xattr:ignore system acls = yes".

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Samba: 4.18.0 - 4.18.7, 4.17.0 - 4.17.11, 4.19.0, 4.16.0 - 4.16.11, 4.15.0 - 4.15.13, 4.14.0 - 4.14.14, 4.13.0 - 4.13.17, 4.12.0 - 4.12.15, 4.11.0 - 4.11.17, 4.10.0 - 4.10.18, 4.9.0 - 4.9.18, 1.9.16 - 1.9.18, 4.8.0 - 4.8.12, 4.7.0 - 4.7.12, 4.6.0 - 4.6.16, 4.5.0 - 4.5.16, 4.4.0 - 4.4.16, 4.3.0 - 4.3.13, 4.2.0 - 4.2.14, 4.1.0 - 4.1.23, 4.0.0 - 4.0.26, 3.6.0 - 3.6.25, 3.5 - 3.5.22, 3.1 - 3.1.0, 3.4 - 3.4.17, 2.2 - 2.2a, 3.3 - 3.3.16, 3.0 - 3.0.37, 3.2 - 3.2.15, 2.18.3, 2.0 - 2.0.10

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External links
http://www.samba.org/samba/security/CVE-2023-4091.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.