CVE-2020-28970

Western Digital MyCloud PR4100 nasAdmin Incorrect Authorization 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

An issue was discovered on Western Digital My Cloud OS 5 devices before 5.06.115. A NAS Admin authentication bypass vulnerability could allow an unauthenticated user to execute privileged commands on the device via a cookie. (In addition, an upload endpoint could then be used by an authenticated administrator to upload executable PHP scripts.)

Se detectó un problema en los dispositivos Western Digital My Cloud OS versiones 5 anteriores a 5.06.115. Una vulnerabilidad de omisión de autenticación de administrador de NAS podría permitir a un usuario no autenticado ejecutar comandos privilegiados en el dispositivo por medio de una cookie. (Además, un endpoint de carga podría ser usado por un administrador autenticado para cargar scripts PHP ejecutables)

This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of Western Digital MyCloud PR4100. Authentication is not required to exploit this vulnerability.
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: Sam Thomas (@_s_n_t) of Pentest Ltd (@pentestltd)

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Physical

Attack Complexity

High

Privileges Required

High

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

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

2020-11-20 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-20-1448	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