(Pwn2Own) Western Digital MyCloud PR4100 FTP Server Buffer Overflow Remote Code Execution Vulnerability

February 9th, 2023
ZDI-23-112 ZDI-CAN-19736

CVE ID

CVE-2022-29844

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 NAS devices. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the FTP server. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length buffer. 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://www.westerndigital.com/support/product-security/wdc-23002-my-cloud-firmware-version-5-26-119

Disclosure Timeline

  • 2022-12-29 - Vulnerability reported to vendor
  • 2023-02-09 - Coordinated public release of advisory

Credit

Luca MORO (@johncool__)

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