Hello, I am one of the developers of the hub.
First of all I would like to ask what kind of technique you are using to decide if a UDP port is open or closed? UDP is connectionless so by design they don’t really behave like TCP when doing port scans. With TCP you often either get a Connection Reset response or no response at all if you try to connect to a closed port, at which point you can assume that the port is actually closed. With UDP it does not work like that since you are not guaranteed to get a response in either scenario. And even if a port is temporarily open it does not mean that you actually have a service on the other side listening.
I seem to remember that tools like NMAP use ICMP responses to decide if a UDP port is open (correct me if I’m wrong). But this generates a lot of false positives since a lot of ports are not really bound to a permanent service, but rather temporary ports used by both the Linux OS (DNS requests, NTP requests, etc..) and our host application for different features (like action executions etc). This is normal UDP behavior and not an indication of a security flaw.
But again, I don’t fully trust the results of this scan. UDP port 22 (SSH) for example I know for sure is not bound to anything.
If you have any further questions then I will try to answer but you need to be more specific with what kind of tools you use and what kind of amplification attacks you are referring to.