Vulnerability identifier: #VU77532

Vulnerability risk: High

CVSSv3.1: 9.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2023-27992

CWE-ID: CWE-78

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
NAS326
Hardware solutions / Routers for home users
NAS540
Hardware solutions / Routers for home users
NAS542
Hardware solutions / Routers for home users

Vendor: ZyXEL Communications Corp.

Description

The vulnerability allows a remote attacker to execute arbitrary shell commands on the target system.

The vulnerability exists due to improper input validation. A remote unauthenticated attacker can pass specially crafted data to the application and execute arbitrary OS commands on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

NAS326: 5.21(AAZF.13)C0

NAS540: 5.21(AATB.10)C0

NAS542: 5.21(ABAG.10)C0

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External links
http://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-pre-authentication-command-injection-vulnerability-in-nas-products

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.