Vulnerability identifier: #VU60186

Vulnerability risk: High

CVSSv3.1: 8.9 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-44142

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: Yes

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

Vendor: Samba

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing EA metadata while opening files in smbd within the VFS Samba module (vfs_fruit). A remote attacker with ability to write to file's extended attributes can trigger an out-of-bounds write and execute arbitrary code with root privileges.

Note, the vulnerability in vfs_fruit exists in the default configuration of the fruit VFS module using fruit:metadata=netatalk or fruit:resource=file.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Samba: 4.15.0 - 4.15.4, 4.14.0 - 4.14.11, 4.13.0 - 4.13.16, 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-2021-44142.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. However, proof of concept for this vulnerability is available.