The latest firmware update released by Western Digital for the My Cloud Mirror personal cloud storage product patches serious remote command execution and authentication bypass vulnerabilities.
ESET researcher Kacper Szurek recently discovered that WD My Cloud Mirror devices running firmware version 2.11.153, which had been the most recent version, were affected by several vulnerabilities caused by the lack of proper user input escaping.
The most serious of the flaws affects the index page of the product’s web interface and it allows an attacker to execute arbitrary commands via the “username” parameter. Commands can be executed using the following line as “username”: a" || your_command_to_execute || "
Szurek also discovered that an attacker can bypass authentication to the WD My Cloud Mirror interface. The problem, according to the expert, is that the function designed to check if the user has logged in can be easily bypassed as it only checks if the “username” and “isAdmin” cookies exist.
An attacker can bypass authentication by setting the values “username=1” and “isAdmin=1,” and then accessing one of the webpages (e.g. php/users.php).
The vulnerabilities were reported to WD in mid-November and they were patched on December 20 with the release of version 2.11.157 of the firmware. The vendor’s release notes describe these issues as a “security vulnerability related to remote access.”
Earlier this month, researcher Steven Campbell also reported finding a couple of flaws in WD’s My Cloud devices, including a command injection issue. The vendor patched the command injection vulnerability (CVE-2016-10108) in December with the release of firmware version 2.21.126. The second bug, tracked as CVE-2016-10107 and described as “variable checking for PHP pages for authenticated users,” will be addressed with an upcoming update.
This was not the first time researchers found security holes in WD’s personal cloud storage products. VerSprite identified a remote command injection vulnerability in My Cloud in September 2015.