What is a Distributed Denial-of-Service (DDoS) attack?
A Distributed Denial-of-Service (DDoS) is a threat to legitimate network services conducted as a computing-resource-originated network attack that uses a number of hosts generating an overwhelming number of malicious service requests. DDoS attacks target online services to cause them to go offline and deny legitimate users access to the online service resources. They are perpetrated for a variety of reasons, including hacktivism, commercial competition, or to accomplish geo-political goals.
There are multiple types of DDoS attacks. An attacker starts the process by taking advantage of a vulnerability in a networked computer server. The hacker makes a compromised computer the DDoS master. Using this as a master system, the hacker detects, communicates and infects other network computers and devices to make them participate in a DDoS attack. A compromised computer or device within the control of a hacker is called a zombie or bot, while a set of compromised network elements is called a zombie army or a botnet.