Vulnerability identifier: #VU34062

Vulnerability risk: Medium

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-13365

CWE-ID: CWE-284

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Zyxel NAS 326
Hardware solutions / Firmware
NAS520
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 user to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions in a CGI script for the web application. A remote authenticated attacker can start a Telnet or SSH service and generate a password for the "NsaRescueAngel" user account with root privileges.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Zyxel NAS 326: All versions

NAS520: All versions

NAS540: All versions

NAS542: All versions

---

CPE

• cpe:2.3:h:zyxel_communications_corp:zyxel_nas_326:*:*:*:*:*:*:*:*
• cpe:2.3:h:zyxel_communications_corp:nas520:*:*:*:*:*:*:*:*
• cpe:2.3:h:zyxel_communications_corp:nas540:*:*:*:*:*:*:*:*
• cpe:2.3:h:zyxel_communications_corp:nas542:*:*:*:*:*:*:*:*

External links
http://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtml

---

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.