DDSO stands for Distribuated Denial Of Service and it is an attack where we block the ressources of a server by flooding it with requests. This kinf of attack is never performed alone but with help of so-collaed botnets.
This a simple ddos client, a script that overload awebsite with request, so that the web site will not be able to work properly(offert service) cauz will overload it's capacity.