That poster was likely me. 
The thread in question deals with one specific vulnerability that was aimed at OS3 My Cloud units (particularly v2.x units). It is not clear if that specific vulnerability even affected the older v4.x firmware single bay My Cloud units.
The OS3 My Cloud firmware likely has a number of security vulnerabilities not just the one mentioned in that thread discussion. The OS3 firmware also has some (many?) outdated modules or portions of code including using an old “beta” version of Twonky Media Server apparently. There are ways to run scripts or call scripts such as that one, at OS3 My Cloud bootup. For example using the file /etc/rc2.d/S98user-start (if it exists on one’s My Cloud) is one method or option.
One way to limit the exposure of the various security vulnerabilities of the OS3 My Cloud units is to block broadband access to the My Cloud at the router firewall. Most consumer routers include the function to block internet/broadband access to a specific network device. Simply turning off Remote Access/Cloud Access in the My Cloud Dashboard > Settings isn’t enough, some of the vulnerabilities may still be exploitable which is why its best to also block broadband access to the My Cloud at the router firewall.
