I like it when your gut feeling proves to be right. Hackernews just published this https://thehackernews.com/2018/01/western-digital-mycloud.html:
“Security researchers have discovered several severe vulnerabilities and a secret hard-coded backdoor in Western Digital’s My Cloud NAS devices that could allow remote attackers to gain unrestricted root access to the device...”
I have one of these devices, and after a first glance I deactivated the software as fast as I could – obviously my intuition was right.