Distributed Denial of Service (DDoS) Attack

Sec+ Glossary 📖 • Network Attacks🎯 • Threats ⚠️ • Network Security 🌐 • Security+ 02 • Difficulty: free

What is Distributed Denial of Service (DDoS) Attack?

A DDoS attack attempts to make a service unavailable by overwhelming it with traffic or resource-intensive requests from many distributed sources. The goal is to exhaust bandwidth, server capacity, or application resources so legitimate users cannot access the service.

Examples

  • An online store receives a sudden flood of traffic from thousands of compromised devices, saturating its internet connection and causing timeouts for real customers.
  • A gaming service is hit with repeated UDP floods that overwhelm network devices, forcing the provider to reroute traffic through a scrubbing service.

Discover 🔎

DDoS attacks are about disruption rather than stealing data. They target availability by drowning a service in traffic or requests until something breaks. Because the traffic comes from many sources, blocking a single IP address does not solve the problem. This makes DDoS a common threat for public websites, online services, and any system that must be reachable from the internet.

Remember: DoS is one source. DDoS is many sources. The “distributed” part is what makes it harder to stop with simple blocking.

Summary 📝

A DDoS attack targets availability by overwhelming a service with distributed traffic. Attacks can flood bandwidth, exhaust infrastructure, or overload applications, often using amplification to multiply power. Effective defense relies on layered resilience: CDN and WAF for web traffic, rate limiting and autoscaling for capacity, and upstream mitigation to stop floods before they saturate your network.

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