An HTTP flood is a more sophisticated type of application-layer DDoS attack that targets the web server itself, rather than the network or transport layers. Let’s break it down:

🌐 What Is an HTTP Flood Attack?

An HTTP flood is a Distributed Denial of Service (DDoS) attack where the attacker sends a massive number of HTTP requests to a web server—just like a normal user would—but at a volume and rate that overwhelms the server’s resources.

Unlike volume-based attacks that flood bandwidth, HTTP floods consume CPU, memory, and application processing power.

🔍 How It Works

1. Botnet Activation: The attacker uses a botnet of infected devices to send HTTP requests.
2. Legitimate-Looking Requests: These requests mimic normal user behavior—like loading a webpage or submitting a form.
3. Resource Drain: The server tries to process each request, which can involve database queries, authentication, or rendering dynamic content.
4. Server Overload: Eventually, the server becomes too busy to respond to real users.

🧠 Why It’s Tricky

• Hard to Detect: Requests look legitimate—no malformed packets or obvious signs of attack.
• No Amplification Needed: The attack relies on volume and complexity, not reflection.
• Targets Application Logic: Especially dangerous for sites with dynamic content or heavy backend processing.

🛠️ Types of HTTP Floods

🧯 How to Defend Against HTTP Floods

• Web Application Firewalls (WAFs): Detect and block suspicious patterns.
• Rate Limiting: Restrict how many requests a user can make in a given time.
• CAPTCHAs: Challenge users to prove they’re human.
• Behavioral Analysis: Use AI or heuristics to spot abnormal traffic patterns.
• Load Balancing: Distribute traffic across multiple servers.

🧪 Real-World Example

HTTP floods have been used to target political websites, financial institutions, and e-commerce platforms. Because they mimic real users, they’re often part of advanced persistent threats (APTs) or hacktivist campaigns.