A DDoS (Distributed Denial of Service) attack occurs when a large number of compromised systems simultaneously send massive amounts of traffic or requests to an application, server, or network. The goal is to exhaust resources such as bandwidth, CPU, memory, or connections, making the service unavailable to legitimate users.
Key Points: • DDoS attacks originate from multiple devices, making them more difficult to detect and block than a traditional DoS attack. • Common prevention techniques include rate limiting, traffic filtering, firewalls, Web Application Firewalls (WAF), and load balancing. • Cloud-based DDoS protection services can absorb and mitigate malicious traffic before it reaches the application.
Example: Consider an online banking application that normally handles 10,000 requests per minute. During a DDoS attack, millions of fake requests are sent from thousands of compromised devices, overwhelming the server and preventing genuine customers from accessing their accounts.
Key Prevention Strategies: • Implement rate limiting to restrict excessive requests from a single source. • Use load balancers to distribute incoming traffic across multiple servers. • Deploy Web Application Firewalls (WAF) to identify and block malicious requests. • Enable traffic monitoring and anomaly detection to identify suspicious spikes in traffic. • Use CDN and cloud-based DDoS protection services to absorb attack traffic.
Interview Tip: A concise interview answer is: A DDoS attack floods an application or server with excessive traffic from multiple sources, making it unavailable to legitimate users. It can be mitigated using rate limiting, firewalls, load balancers, traffic monitoring, WAFs, and cloud-based DDoS protection services that filter and absorb malicious traffic.