CVE-2020-28940

Western Digital MyCloud PR4100 nasAdmin Authentication Bypass Vulnerability

Severity Score

9.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

On Western Digital My Cloud OS 5 devices before 5.06.115, the NAS Admin dashboard has an authentication bypass vulnerability that could allow an unauthenticated user to execute privileged commands on the device.

En los dispositivos Western Digital My Cloud OS 5 versiones anteriores a 5.06.115, el panel de administración de NAS presenta una vulnerabilidad de omisión de autenticación que podría permitir a un usuario no autenticado ejecutar comandos privilegiados en el dispositivo

This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of Western Digital MyCloud PR4100. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed.
The specific flaw exists within the nasAdmin service, which listens on TCP port 80 and 443 by default. The issue results from incorrect string matching logic when accessing protected pages. An attacker can leverage this vulnerability to execute arbitrary code in the context of root.

*Credits: Lays (@_L4ys)

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-11-19 CVE Reserved
2020-12-01 CVE Published
2024-06-10 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-287: Improper Authentication

CAPEC

References (3)

URL	Tag	Source
https://www.zerodayinitiative.com/advisories/ZDI-20-1445	Third Party Advisory

URL	Date	SRC

URL	Date	SRC
https://support.wdc.com/downloads.aspx?g=907&lang=en#downloads	2022-04-26

URL	Date	SRC
https://www.westerndigital.com/support/productsecurity/wdc-20009-os5-firmware-5-06-115	2022-04-26

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Westerndigital Search vendor "Westerndigital"	My Cloud Os 5 Search vendor "Westerndigital" for product "My Cloud Os 5"	< 5.06.115 Search vendor "Westerndigital" for product "My Cloud Os 5" and version " < 5.06.115"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Ex2 Ultra Search vendor "Westerndigital" for product "My Cloud Ex2 Ultra"	-	-	Safe
Westerndigital Search vendor "Westerndigital"	My Cloud Os 5 Search vendor "Westerndigital" for product "My Cloud Os 5"	< 5.06.115 Search vendor "Westerndigital" for product "My Cloud Os 5" and version " < 5.06.115"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Ex4100 Search vendor "Westerndigital" for product "My Cloud Ex4100"	-	-	Safe
Westerndigital Search vendor "Westerndigital"	My Cloud Os 5 Search vendor "Westerndigital" for product "My Cloud Os 5"	< 5.06.115 Search vendor "Westerndigital" for product "My Cloud Os 5" and version " < 5.06.115"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Mirror Gen 2 Search vendor "Westerndigital" for product "My Cloud Mirror Gen 2"	-	-	Safe
Westerndigital Search vendor "Westerndigital"	My Cloud Os 5 Search vendor "Westerndigital" for product "My Cloud Os 5"	< 5.06.115 Search vendor "Westerndigital" for product "My Cloud Os 5" and version " < 5.06.115"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Pr2100 Search vendor "Westerndigital" for product "My Cloud Pr2100"	-	-	Safe
Westerndigital Search vendor "Westerndigital"	My Cloud Os 5 Search vendor "Westerndigital" for product "My Cloud Os 5"	< 5.06.115 Search vendor "Westerndigital" for product "My Cloud Os 5" and version " < 5.06.115"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Pr4100 Search vendor "Westerndigital" for product "My Cloud Pr4100"	-	-	Safe