In my opinion, it’s probably not only the AICloud services but also the Asus DDNS service that is affected.
Infact, the Asus DDNS service was also vulnerable because the process for updating records did not have specific security safeguards.
A simple request with potentially “valid” data -such as the MAC address of another Asus device, which can be easily found through basic web searches- was enough to modify a record.
In this scenario, a malicious actor could redirect the DDNS record to their own server: this would then capture any unencrypted access credentials (which are
not encrypted but merely encoded in Base64) sent by the ASUS Router app, giving them direct access to the device.
This risk, however, only applies *if* web access from the WAN is enabled and the Asus DDNS service is in use.
Details of this vulnerability on the Black Hat Briefing
here which includes slides that explain the exploitation process in detail.
At this point, it’s still unclear whether Asus has fixed this flaw (i.e., the lack of proper verification when updating records).
Personally, I am switching to a more secure DDNS provider as a precaution.