GLOSSARY / DDoS Attack
What is DDoS Attack?
A Distributed Denial-of-Service attack floods a target with traffic from many sources to make it unavailable.
DDoS attacks use botnets or reflection/amplification (DNS, NTP, memcached) to overwhelm bandwidth, connection state, or application resources. They range from volumetric floods to subtle layer-7 attacks that exhaust application logic.
They are often used for extortion, as a distraction during another intrusion, or for hacktivism.
How to defend
Use a CDN/scrubbing service, rate limiting, and anycast routing; filter spoofed traffic upstream.
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Part of the Ciphers Security glossary. Free reference for analysts, defenders & learners.