Recommended Security Measures for WD My Book Live and WD My Book Live Duo

WDC Tracking Number: WDC-21008
Product Line: WD My Book Live and WD My Book Live Duo
Published: June 24, 2021

Last Updated:  July 6, 2021

Western Digital has determined that Internet-connected My Book Live and My Book Live Duo devices are under attack by exploitation of multiple vulnerabilities present in the device. In some cases, the attackers have triggered a factory reset that appears to erase all data on the device.

Data Recovery and Product Trade-In Programs
Western Digital is offering a data recovery service program to help customers who have lost data as a result of these attacks. My Book Live customers are also offered a trade-in program to upgrade to a supported My Cloud device. You can find more details on these programs by following the links below:

Analysis of Newly Identified Vulnerability CVE-2021-35941

The My Book Live firmware is vulnerable to a remotely exploitable command injection vulnerability when the device has remote access enabled. This vulnerability may be exploited to run arbitrary commands with root privileges. Additionally, the My Book Live is vulnerable to an unauthenticated factory reset operation which allows an attacker to factory reset the device without authentication. The unauthenticated factory reset vulnerability been assigned CVE-2021-35941.

We have heard concerns about the nature of this vulnerability and are sharing technical details to address these questions. We have determined that the unauthenticated factory reset vulnerability was introduced to the My Book Live in April of 2011 as part of a refactor of authentication logic in the device firmware. The refactor centralized the authentication logic into a single file, which is present on the device as includes/component_config.php and contains the authentication type required by each endpoint. In this refactor, the authentication logic in system_factory_restore.php was correctly disabled, but the appropriate authentication type of ADMIN_AUTH_LAN_ALL was not added to component_config.php, resulting in the vulnerability. The same refactor removed authentication logic from other files and correctly added the appropriate authentication type to the component_config.php file.

Analysis of the Attack
We have reviewed log files which we have received from affected customers to understand and characterize the attack. The log files we reviewed show that the attackers directly connected to the affected My Book Live devices from a variety of IP addresses in different countries. Our investigation shows that in some cases, the same attacker exploited both vulnerabilities on the device, as evidenced by the source IP. The first vulnerability was exploited to install a malicious binary on the device, and the second vulnerability was later exploited to reset the device.

On some devices, the attackers installed a trojan with a file named .nttpd,1-ppc-be-t1-z, which is a Linux ELF binary compiled for the PowerPC architecture used by the My Book Live and Live Duo. A sample of this trojan has been captured for further analysis and it has been uploaded to VirusTotal.

Our investigation of this incident has not uncovered any evidence that Western Digital cloud services, firmware update servers, or customer credentials were compromised. As the My Book Live devices can be directly exposed to the internet through port forwarding, the attackers may be able to discover vulnerable devices through port scanning. The vulnerabilities being exploited in this attack are limited to the My Book Live series, which was introduced to the market in 2010 and received a final firmware update in 2015. These vulnerabilities do not affect our current My Cloud product family.

Affected Products

My Book Live
My Book Live
My Book Live
My Book Live Duo
My Book Live Duo
My Book Live Duo

Advisory Summary

Immediately disconnect your My Book Live and My Book Live Duo from the Internet to protect your data from ongoing attacks.

For customers who have lost data as a result of these attacks, Western Digital will provide data recovery services. Western Digital is also offering My Book Live customers a trade-in program to upgrade to a supported My Cloud device.

CVE Numbers: CVE-2018-18472 and CVE-2021-35941