HTTPflood

HTTP flood is a form of denial-of-service attack that targets a web server by overwhelming it with HTTP requests. It operates at the application layer and aims to exhaust server resources needed to process requests, rather than simply saturating network bandwidth. Attackers may recruit large numbers of compromised devices or use automated scripts to generate high volumes of HTTP GET and POST requests, often with the appearance of normal user traffic.

The defining characteristic of HTTP floods is their reliance on legitimate protocol interactions. Attack patterns include GET floods, POST floods, or mixed patterns, sometimes with randomized headers, cookies, or payloads to avoid simple signature matching. Some techniques maintain persistent sessions, exploit slow request behaviors, or use encrypted connections to complicate inspection.

Impact can range from degraded response times to full service outage. Because the threat targets application resources, impact is most pronounced on sites with dynamic content, frequent database access, or limited server capacity. HTTP floods can be difficult to distinguish from legitimate spikes in traffic without detailed traffic analysis.

Mitigation is typically multi-layered. Defenses may include rate limiting, web application firewalls, and content delivery networks that cache and absorb traffic. Bot management, device fingerprinting, and behavior-based anomaly detection help differentiate legitimate users from automated traffic. Incident response practices, logging, and continuous monitoring are important for recognizing patterns and restoring service while minimizing collateral damage.