CVE-2021-3310

Western Digital MyCloud PR4100 Link Resolution Information Disclosure Vulnerability

Severity Score

7.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

Western Digital My Cloud OS 5 devices before 5.10.122 mishandle Symbolic Link Following on SMB and AFP shares. This can lead to code execution and information disclosure (by reading local files).

Los dispositivos Western Digital My Cloud OS 5 versiones anteriores a 5.10.122, manejan inapropiadamente recursos compartidos de Symbolic Link Following en SMB y AFP. Esto puede conllevar a una ejecución de código y divulgación de información (mediante la lectura de archivos locales)

This vulnerability allows remote attackers to disclose sensitive information on affected installations of Western Digital MyCloud PR4100. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the SMB and AFP services. By creating a symbolic link, an attacker can abuse the service to read arbitrary files. An attacker can leverage this vulnerability to disclose information in the context of the service account.

*Credits: Chris Hernandez

CVSS Scores

Attack Vector

Local

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

High

Integrity

None

Availability

None

Attack Vector

Local

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

2021-01-26 CVE Reserved
2021-03-10 CVE Published
2021-05-24 First Exploit
2023-03-08 EPSS Updated
2024-08-03 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-59: Improper Link Resolution Before File Access ('Link Following')

CAPEC

References (3)

URL	Tag	Source
https://www.zerodayinitiative.com/advisories/ZDI-21-277	Third Party Advisory

URL	Date	SRC
https://github.com/piffd0s/CVE-2021-3310	2021-05-24

URL	Date	SRC

URL	Date	SRC
https://www.westerndigital.com/support/productsecurity/wdc-21002-my-cloud-firmware-version-5-10-122	2021-03-17

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 Search vendor "Westerndigital" for product "My Cloud Os"	< 5.10.122 Search vendor "Westerndigital" for product "My Cloud Os" and version " < 5.10.122"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Dl2100 Search vendor "Westerndigital" for product "My Cloud Dl2100"	-	-	Safe
Westerndigital Search vendor "Westerndigital"	My Cloud Os Search vendor "Westerndigital" for product "My Cloud Os"	< 5.10.122 Search vendor "Westerndigital" for product "My Cloud Os" and version " < 5.10.122"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Dl4100 Search vendor "Westerndigital" for product "My Cloud Dl4100"	-	-	Safe
Westerndigital Search vendor "Westerndigital"	My Cloud Os Search vendor "Westerndigital" for product "My Cloud Os"	< 5.10.122 Search vendor "Westerndigital" for product "My Cloud Os" and version " < 5.10.122"	-	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 Search vendor "Westerndigital" for product "My Cloud Os"	< 5.10.122 Search vendor "Westerndigital" for product "My Cloud Os" and version " < 5.10.122"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Ex2100 Search vendor "Westerndigital" for product "My Cloud Ex2100"	-	-	Safe
Westerndigital Search vendor "Westerndigital"	My Cloud Os Search vendor "Westerndigital" for product "My Cloud Os"	< 5.10.122 Search vendor "Westerndigital" for product "My Cloud Os" and version " < 5.10.122"	-	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 Search vendor "Westerndigital" for product "My Cloud Os"	< 5.10.122 Search vendor "Westerndigital" for product "My Cloud Os" and version " < 5.10.122"	-	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 Search vendor "Westerndigital" for product "My Cloud Os"	< 5.10.122 Search vendor "Westerndigital" for product "My Cloud Os" and version " < 5.10.122"	-	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 Search vendor "Westerndigital" for product "My Cloud Os"	< 5.10.122 Search vendor "Westerndigital" for product "My Cloud Os" and version " < 5.10.122"	-	Affected	in	Westerndigital Search vendor "Westerndigital"	My Cloud Pr4100 Search vendor "Westerndigital" for product "My Cloud Pr4100"	-	-	Safe