CVE-2020-13364

Severity Score

8.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

A backdoor in certain Zyxel products allows remote TELNET access via a CGI script. This affects NAS520 V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, and V5.11(AASZ.0)C0; NAS542 V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, and V5.21(ABAG.3)C0; NSA325 v2_V4.81(AALS.0)C0 and V4.81(AAAJ.1)C0; NSA310 4.22(AFK.0)C0 and 4.22(AFK.1)C0; NAS326 V5.21(AAZF.8)C0, V5.11(AAZF.4)C0, V5.11(AAZF.2)C0, and V5.11(AAZF.3)C0; NSA310S V4.75(AALH.2)C0; NSA320S V4.75(AANV.2)C0 and V4.75(AANV.1)C0; NSA221 V4.41(AFM.1)C0; and NAS540 V5.21(AATB.5)C0 and V5.21(AATB.3)C0.

Una backdoor en determinados productos Zyxel permite el acceso remoto a TELNET por medio de un script CGI. Esto afecta a NAS520 V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, and V5.11(AASZ.0)C0; NAS542 V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, and V5.21(ABAG.3)C0; NSA325 v2_V4.81(AALS.0)C0 and V4.81(AAAJ.1)C0; NSA310 4.22(AFK.0)C0 and 4.22(AFK.1)C0; NAS326 V5.21(AAZF.8)C0, V5.11(AAZF.4)C0, V5.11(AAZF.2)C0, and V5.11(AAZF.3)C0; NSA310S V4.75(AALH.2)C0; NSA320S V4.75(AANV.2)C0 and V4.75(AANV.1)C0; NSA221 V4.41(AFM.1)C0; and NAS540 V5.21(AATB.5)C0 and V5.21(AATB.3)C0

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Low

Authentication

Single

Confidentiality

Complete

Integrity

Complete

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-05-21 CVE Reserved
2020-08-06 CVE Published
2023-03-07 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (2)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtml	2022-02-09
https://www.zyxel.com/us/en/support/security_advisories.shtml	2022-02-09

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Zyxel Search vendor "Zyxel"	Nas326 Firmware Search vendor "Zyxel" for product "Nas326 Firmware"	< v5.21\(aazf.9\)c0 Search vendor "Zyxel" for product "Nas326 Firmware" and version " < v5.21\(aazf.9\)c0"	-	Affected	in	Zyxel Search vendor "Zyxel"	Nas326 Search vendor "Zyxel" for product "Nas326"	-	-	Safe
Zyxel Search vendor "Zyxel"	Nas520 Firmware Search vendor "Zyxel" for product "Nas520 Firmware"	< v5.21\(aasz.5\)c0 Search vendor "Zyxel" for product "Nas520 Firmware" and version " < v5.21\(aasz.5\)c0"	-	Affected	in	Zyxel Search vendor "Zyxel"	Nas520 Search vendor "Zyxel" for product "Nas520"	-	-	Safe
Zyxel Search vendor "Zyxel"	Nas540 Firmware Search vendor "Zyxel" for product "Nas540 Firmware"	< v5.21\(aatb.6\)c0 Search vendor "Zyxel" for product "Nas540 Firmware" and version " < v5.21\(aatb.6\)c0"	-	Affected	in	Zyxel Search vendor "Zyxel"	Nas540 Search vendor "Zyxel" for product "Nas540"	-	-	Safe
Zyxel Search vendor "Zyxel"	Nas542 Firmware Search vendor "Zyxel" for product "Nas542 Firmware"	< v5.21\(abag.6\)c0 Search vendor "Zyxel" for product "Nas542 Firmware" and version " < v5.21\(abag.6\)c0"	-	Affected	in	Zyxel Search vendor "Zyxel"	Nas542 Search vendor "Zyxel" for product "Nas542"	-	-	Safe