Today, let’s discuss something more insidious—did you think DDoS attacks are all about overwhelming traffic? Wrong! There is a type of attack that disguises itself as a normal user, using legitimate requests to drain your server, known as the pinnacle of “legitimate scamming”! It is the HTTP Flood, colloquially referred to as the “Single Madman”—it can take you down with just a single thread!
HTTP Flood: A Wolf in Sheep’s ClothingAttackers control a large number of “zombie computers” or proxy IPs, bombarding the server with seemingly normal HTTP requests, such as refreshing product pages, submitting forms, or accessing APIs. The frequency of these requests is absurdly high, but each packet looks benign—when the server sees it, it thinks: “Oh, a normal user!” As a result, the CPU explodes!
Three Deadly Moves:
- Resource Black Hole: Specifically targets high-cost interfaces like database queries and file downloads, treating CPU and memory like paper.
- Connection Occupation: Uses long connections to exhaust the TCP connection pool, preventing new users from connecting and causing existing users to lag.
- Business Chain Reaction: Frontend lag → Backend thread pool full → Database crash → Log server paralysis, all at once!
For example: During a major e-commerce promotion, an attacker used 1,000 zombie computers to send 500 “flash sale” requests per second. The result:• Normal users: Page load times out, they complain and cancel orders.
• Server: CPU spikes to 99%, database connection pool explodes, and operations staff are in shock!
Three Defense Strategies: From ‘Manual Security Checks’ to ‘Secret Code Verification’1. WAF Firewall: Equip the server with a “manual security check”• Rule Filtering: Intercepts malicious parameters containing SQL injection or XSS, such as<span>?id=1' AND 1=1--</span>.
• Rate Limiting: A maximum of 10 requests per second from the same IP; exceeding this will result in an immediate ban!
2. Source Authentication: Send a “secret code” with requests• JavaScript Redirection: Normal users’ browsers will execute JS verification, while attack scripts will be confused.
• CAPTCHA Interception: A CAPTCHA pops up after reaching a threshold, causing bots to give up.
3. Traffic Cleaning: Use a “sieve” to filter out the bad• Cloud Service Provider’s Advanced Technology: Huawei Anti-DDoS, Cloudflare intercepts abnormal traffic through request fingerprint recognition (such as specific header combinations).
• Load Balancing Backup: Redirect attack traffic to backup servers, keeping core business stable.
Real-World Case: A Live Streaming Platform’s “Black Friday”Last year’s Double Eleven, a platform was hit by an HTTP Flood attack, receiving 100,000 “gift donation” requests per second, causing the host’s gift effects to lag like a PowerPoint presentation.Response Actions:
- Emergency WAF Activation: Intercept requests with abnormal parameters, such as
<span>/pay?amount=99999999</span>. - Dynamic Rate Limiting: Automatically throttle high-frequency IPs, ensuring legitimate users are unaffected.
- CDN Caching: Cache static resources of the homepage to edge nodes, bypassing attack traffic.Result: Recovery in 20 minutes, the host maintains KPI, and the boss keeps their hairline!
Expert Commentary: Defense is not about “hardware competition”, but “intelligence competition”
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Three Major Self-Sabotaging Actions by Enterprises:• Blindly increasing bandwidth → money wasted, attackers benefit.
• Relying on hardware firewalls → attackers bypass rules and directly exploit vulnerabilities.
• Blaming operations after the fact → “The server quality is poor!” (In reality, the defense strategy was inadequate)
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Protocol Layer Defense is Key:• HTTP Flood specifically targets the application layer, and traditional firewalls cannot stop it!
• Must combine behavioral analysis (such as user behavior profiling) and dynamic verification (such as JS challenges).
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Cloud Protection Success Stories:• A bank used Huawei Cloud ADS, cleaning attack traffic in 10 seconds with zero impact on business.
• A gaming company relied on Cloudflare Bot Management, directly eliminating 99% of bot traffic.
Thought-Provoking Questions: What would you do if you were attacked?• If you are an operations staff member, would you activate WAF first or blacklist the IP first?
• If you are a boss, would you allocate an extra 10% of the budget for defense or blame the team for incompetence?
(Just saying) If you encounter an unmanageable attack, send them this—”108 Ways to Die from HTTP Flood”.
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