Western Digital released new firmware to mitigate vulnerabilities on MyCloud devices that could allow unauthorized file deletion, unauthorized command execution and authentication bypass.
The vulnerabilities were in the MyCloud personal storage device and were reported to Western Digital last year.
Trustwave security researcher Martin Rakhmanov found the issues in the nas_sharing.cgi binary.
The first of them was the inclusion of hardcoded credentials in the binary, which could allow anyone to authenticate to the device.
The hardcoded username was “mydlinkBRionyg” and represents an issue that other security researchers found.
The nas_sharing.cgi binary would also allow any user to execute shell commands as root. An attacker looking to exploit the issue can use the “artist” parameter to execute a command to create a file, for example, Rakhmanov said in a post.
The same faulty binary can be used for arbitrary file deletion, an operation possible through manipulating the “path” parameter, Rakhmanov said. A command using the “path” parameter can be passed using base64 encoding, the same as with the “artist” parameter.
“Usually on embedded systems many processes run unrestricted (i.e. as root) so no security checks are performed at all once a command (file deletion in this case) is about to execute,” Rakhmanov said.
Rakhmanov also published proof of concept code that combines the hardcoded credential issue with command execution and arbitrary file deletion, respectively.
Western Digital said it resolved these issues with the release of firmware version 2.30.172 a couple of months ago.
The update patched a SMB server (samba) security vulnerability, along with “critical security vulnerabilities that potentially allowed unauthorized file deletion, unauthorized command execution and authentication bypass,” the company said in the release notes.