(Pwn2Own) Western Digital MyCloud PR4100 samba Configuration Remote Code Execution Vulnerability

February 15th, 2022
ZDI-22-346 ZDI-CAN-15804

CVE ID

CVSS Score

8.8 AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors

Western Digital

Affected Products

MyCloud PR4100

Vulnerability Details

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Western Digital MyCloud PR4100. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the configuration of the samba service. A crafted request can cause the service to overwrite a file. An attacker can leverage this vulnerability to execute code in the context of root.

Additional Details

Western Digital has issued an update to correct this vulnerability. More details can be found at:
https://os5releasenotes.mycloud.com/#/

Disclosure Timeline

  • 2021-12-01 - Vulnerability reported to vendor
  • 2022-02-15 - Coordinated public release of advisory

Credit

Corentin BAYET (@OnlyTheDuck), Etienne HELLUY-LAFONT and Luca MORO (@johncool__) from Synacktiv

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