What to do if an APP application is subjected to a DDoS attack, and how to defend against it?

DDoS attacks are a type of security threat aimed at disrupting network resources such as applications, websites, servers, and routers, causing significant damage to the victim. However, these attacks can be prevented by implementing security best practices and preparing in advance — such as strengthening the network, configuring resources, deploying robust protection measures, planning ahead, and proactively monitoring the network. Today, CDN5 Network Security Engineer Sam will provide you with the ultimate beginner-friendly protection guide. I hope you find it helpful!

 I. Common DDoS Attack Methods Targeting Apps

1. Imitating Real Users with Slow Attacks:
   Simulates real user behavior, slowly sending requests to bypass traditional interception rules, resulting in a DDoS attack on the app.
2. Global Collaborative Attacks:
   Uses cloud servers, data centers, or botnets from different countries to launch attacks on the app, making traditional IP blacklist strategies ineffective.
3. Multi-layered Attacks:
   Combines high-frequency SELECT * queries to exhaust IOPS, fake video streams to consume bandwidth, and sustained WebSocket connections to drain the target's memory.
4. AI-Assisted Attacks:
   Employs AI to simulate normal user behavior, bypass WAF and security rules, automatically learn and intensify the attack frequency, and dynamically generate attack parameters.

II. Defense Tactics

1. Strengthening App Security

Building a multi-layered network security defense system is the best strategy against DDoS attacks. Common basic security measures, like vulnerability patching, can further enhance protection.

• Timely Patching and Resource Updates: Perform vulnerability scans and API port inspections on the app, promptly fix and encrypt vulnerabilities.
• Penetration Testing for Vulnerability Detection: Fix misconfigurations or security gaps — for example, enforce CAPTCHA on login/registration to counter bots.
• Remove Unnecessary Features: Restrict network ports, set rate limits, block half-open connections, and configure firewalls.

2. Deploying a DDoS Defense Architecture

Besides strengthening app security, apps need a resilient defense configuration, including:

• Provision Excessive Baseline Bandwidth: To withstand sudden DDoS spikes.
• Backup Components: Configure redundant devices to ensure fast recovery after an attack.
• Add Redundancy: Separate firewalls and routers, distribute resources to the cloud to avoid single points of failure.
• Hide APIs and IPs: Mask IPs and API endpoints, add extra security layers, and block ping/ICMP requests.

3. Integrating CDN5 App Security Shield

The best app protection involves integrating the SDK provided by a CDN vendor. With localized traffic forwarding, this method effectively blocks DDoS attacks and prevents CC attacks. CDN5's app shield offers:

• Fast Integration: No complex operations required — even beginners can quickly integrate the SDK.
• Intelligent Routing: SDK dynamically routes content based on the user’s IP, enhancing loading speeds.
• Secure Component Communication: Restricts Intent data transmission, filters malicious Scheme, and verifies Binder interface signatures — only authorized apps can access.
• Anti-Debugging & Reverse Engineering Protection: Uses code obfuscation and dynamic loading to prevent decompilation, encrypts key algorithms with VMP (Virtual Machine Protection), detects debugger connections (e.g., ptrace injection), and triggers circuit breakers or auto-terminates processes when tampering is detected.
• Fraud Prevention: An AI monitoring center identifies abnormal requests in real-time, automatically intervenes, and blocks middle-layer attacks like database tampering and fake users.

III. Three DDoS Defense Strategies: Pros and Cons