VDB-159342 · CVE-2020-13364 · GCVE-0-2020-13364

ZyXEL NAS542 CGI Script backdoor

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.8	$0-$5k	0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in ZyXEL NSA221, NSA310, NSA320S, NSA325, NAS326, NAS520, NAS540 and NAS542. The impacted element is an unknown function of the component CGI Script. The manipulation results in backdoor. This vulnerability is reported as CVE-2020-13364. The attack can be launched remotely. No exploit exists. Applying restrictive firewalling is recommended.

Detailsinfo

A vulnerability was found in ZyXEL NSA221, NSA310, NSA320S, NSA325, NAS326, NAS520, NAS540 and NAS542. It has been classified as critical. Affected is an unknown functionality of the component CGI Script. The manipulation with an unknown input leads to a backdoor vulnerability. CWE is classifying the issue as CWE-912. The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was disclosed 08/06/2020. This vulnerability is traded as CVE-2020-13364 since 05/21/2020. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1588.001 by the MITRE ATT&CK project.

It is possible to mitigate the weakness by firewalling .

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Productinfo

Vendor

ZyXEL

Name

License

commercial

Website

Vendor: https://www.zyxel.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.9
VulDB Meta Temp Score: 6.8

VulDB Base Score: 7.3
VulDB Temp Score: 7.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 6.5
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Backdoor
CWE: CWE-912
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Firewall
Status: 🔍

0-Day Time: 🔍

Timelineinfo

05/21/2020 🔍
08/06/2020 +77 days 🔍
08/07/2020 +1 days 🔍
11/07/2020 +92 days 🔍

Sourcesinfo

Vendor: zyxel.com

Status: Not defined

CVE: CVE-2020-13364 (🔍)
GCVE (CVE): GCVE-0-2020-13364
GCVE (VulDB): GCVE-100-159342

Entryinfo

Created: 08/07/2020 08:32
Updated: 11/07/2020 09:41
Changes: 08/07/2020 08:32 (35), 08/07/2020 08:37 (11), 11/07/2020 09:41 (1)
Complete: 🔍
Cache ID: 216::103