We have noticed that the UCP page can send unlimited reset password that can possibly leads to DOS.
Is it possible to limit this into twice and there is countdown time before the user can send again or if none, is there a way to totally disable the “Forgot Password” button?
I am not aware of any built-in way to toggle this. There is Sangoma responsive firewall which can block IPs after it sees a series of failures, but an ever-changing IP will negate that.
You could approach this in two ways:
Assume this is a bug and submit a bug report and see what Sangoma says.
Assume this is feature request and submit a feature request.