A Distributed Denial of Service (DDoS) attack occurs when multiple computers, often compromised by malware, flood a target server or network with excessive traffic. This overwhelming influx of requests makes it difficult or impossible for legitimate users to access the service, effectively causing a shutdown. DDoS attacks can be orchestrated using a network of infected devices, known as a botnet. These attacks can target various online services, including websites, gaming servers, and even cloud services, leading to significant downtime and financial losses for businesses and organizations.