A distributed denial-of-service attack occurs when multiple systems generate large volumes of traffic or requests to overwhelm a target. The goal is to degrade or deny availability of a service, application, or network resource. A target overwhelmed by a flood of traffic is therefore the correct scenario. Information extracted without host knowledge describes data exfiltration. A malicious payload concealed in a file may describe a trojan or weaponized document. An email with a malicious attachment is a delivery mechanism, often used in phishing or malware campaigns. DDoS attacks often use botnets made of compromised devices, including servers, endpoints, and IoT systems. Defenses may include rate limiting, upstream filtering, content delivery networks, scrubbing services, resilient architecture, and incident response planning. DDoS is fundamentally an availability attack: it tries to make legitimate users unable to access services by exhausting capacity or application resources. Reference/topics: Cybersecurity 1.3, common attack types; Security Operations 6.3, incident response planning.