Denial Of Service – Denial of Service Attack is a type of cyber attack made to render services inoperable and inaccessible by sending a large number of connection requests to services such as servers, applications, devices and network resources in the targeted organization. It causes a late response to the requests of users who create legitimate traffic by demanding more services from the resources they have, or a denial of service with no response at all.
In case of a large number of distributed hosts managed from a center, Distributed Denial of Service (Distributed Denial of Service Attack) occurs.
In order for a DDoS attack to occur, the malware to be used in the attack must be infected on the target machine. Infected machines are called “zombies”. (also called daemons, agents, slaves, or bots)
DDoS attacks are divided into 2 basic classes as volume-based or exploit-based. Against volume-based attacks, defense against DDoS attack is made by using Threshold or Learning-based methods. In exploit-based attacks, exploit signatures are used to prevent exploits from damaging the system.