is a broad class of cyberattack that disrupts online services and resources by overwhelming them with traffic. This renders the targeted online service unusable for the duration of the DDoS attack. The hallmark of DDoS attacks is the distributed nature of the malicious traffic, which typically originates from a botnet—a criminally-controlled network of compromised machines spread around the globe.

• Volumetric attacks: The classic types of DDoS, these attacks employ methods to generate massive volumes of traffic to completely saturate bandwidth, creating a traffic jam that makes it impossible for legitimate traffic to flow into or out of the targeted site.
• Protocol attacks: Protocol attacks are designed to eat up the processing capacity of network infrastructure resources like servers, firewalls, and load balancers by targeting Layer 3 and Layer 4 protocol communications with malicious connection requests.
• Application attacks: Some of the more sophisticated DDoS attacks, these exploit weaknesses in the application layer—Layer 7—by opening connections and initiating process and transaction requests that consume finite resources like disk space and available memory.

• Business competition: In competitive industries a DDoS attack can be used to take down a rival’s website.
• Extortion: Certain industries, such as e-commerce, are dependent on their online presence and are easy prey for perpetrators extorting money in exchange for keeping a specific website online.
• Hacktivism: Hacktivists typically target political, media, or corporate websites to protest their actions.
• Vandalism: Cyber vandals, typically disgruntled users or random offenders, often attack high-profile targets.