What to do when APP application is attacked by DDOS, effective protection and emergency measures

What is DDOS attack?  

DDoS attack is Distributed Denial of Service attack, is a common and very difficult to defend against the attacker by controlling a large number of botnets (puppet machines), like the target server to send a large number of malicious requests, consume the server's resources, thus forcing the server to go down.

For example, you now open a coffee shop, the store is only 30 square meters, usually normal can only accommodate 10 people, suddenly today came 1000 people, these people are not real customers, is malicious, your coffee shop instantly burst, completely unable to normal business.

Types of DDOS Attacks 

Transport Layer DDos Attacks: (Syn Flood, Ack Flood, UDP Flood, ICMP Flood, RstFlood), DNS DDos Attacks, Connection-based DDos Attacks, Web Application Layer DDos Attacks (HTTP Get Flood, HTTP Post Flood, CC)  
Network Layer Attacks: (UDP Reflection Attacks) - Transport Layer Attacks (SYN Flood Attacks, Connection Count Attacks) - Session Layer Attacks (SSL Connection Attacks) - Application Layer Attacks (DNS flood Attacks, HTTP flood Attacks (i.e. CC Attacks), Gaming Dummy Attacks) 

Regardless of the tpe of attack, the target is ultimately the same, to name a few common types to illustrate:

• Capacity
• Protocol
• Application

These three types of attacks are divided into many types, such as UDP, ICMP, IP, TCP, http flooding and other variants, as well as the current AI coordinated attacks. The following CDN5 engineers speak for the above types in the gradual expansion of the explanation.  
1. Capacity Consumption Attacks  
As the name suggests, capacity consumption is to make the target server request more than the load through the attack, and then run out, including UDP, CHARGEN, ICMP  
UDP flood attack  
UDP protocol, through the port to send packets to the target, the current server will automatically process after receiving the packet, the attacker through the IP address and port embedded in the UDP packet to attack the server within the network, through a large number of requests to exhaust the target. Common ones include, DNS, NTP, SSDP, Voice over IP, p2p, SNMP, QOTD, STEAM and so on. Variants include, UDP fragmentation, UDP amplification attacks (protocols are usually SNMP,SSDP,NTP)  
CharGEN Flooding    
CharGEN protocol originated from 1983, its purpose is to be used for debugging, measuring, requesting port 19 to send a TCP or UDP request to trigger, the attacker usually forges the IP address of the target server, running CharGEN networking devices to send a request, and then these devices respond to the request, bombarded with port 19, if the firewall does not block the port 19, then it will run down.  
ICMP flooding  
Internet Control Message Protocol consists of specific messages or operational commands sent between networked devices, such as timestamps, timeout errors, echo requests ping commands, etc. Attackers consume incoming and outgoing broadband by sending a large number of spoofed ping packets. There are also now ICMP fragmentation attacks, which work on a similar principle.  
Misuse of applications  
The attacker obtains high traffic applications from legitimate servers and redirects them to the target server. Since the packets sent appear to be normal requests, most defense tools misjudge them, causing the server to overwhelm and go down.

3. Impact of the attack on APP business:     

Direct loss: service interruption leads to user loss, transaction failure, and brand trust decline.    

Hidden risk: the attack may mask other security threats such as data theft and ransomware implantation    

Compliance risk: failure to respond in a timely manner may violate data protection regulations (e.g., GDPR) and face legal recourse      

If you are suffering from DDOS attacks, the best way is to directly access the CDN5 protection SDK: Consult now!   

4.APP how to defend against DDOS attacks   

Architecture Optimization   

Adopt distributed architecture, split the business into independent modules, such as user authentication, payment interface, etc., deployed in different server clusters to avoid single point of failure.   

Purchase elastic resources from cloud service providers: e.g. use Google cloud servers with dynamic quotas for elastic traffic.   

 Close unneeded protocols and ports: Close all unneeded ones.   

Multi-layer defense    

High-defense IP and high-defense CDN: Purchase CDN5 high-defense IP or high-defense CDN, and distribute them through nodes to cope with attack traffic and clean malicious requests.   

Behavior Analysis Engine: Use AI algorithm to identify abnormal patterns. For example, a single IP launching 100 login requests in 1 second can be judged as an attack.        
Rate limiting and blacklisting: set limit_req_zone in Nginx configuration to limit request frequency and automatically block abnormal IPs.      

WAF Integration   

Rule base matching: Enable Web Application Firewall (e.g. CDN5 WAF, Cloudflare rule set) to block SQL injection, XSS and other vulnerability exploits.        
Human-computer authentication: Trigger CAPTCHA authentication on suspicious requests to distinguish real users from automated scripts.      

API security reinforcement: using OAuth 2.0 authentication, request signatures, timestamp verification, to prevent the API interface from being abused.    

5. How to choose an APP security protection provider?   

1. Ensure T-level protection, and flexible broadband and real-time cleaning capabilities.   

2. Is SDK quick to integrate? CDN5's SDK development kit is simple to integrate, fast to access, and ignores DDOS and CC attacks.   

3. After-sales support: whether the service provider can respond at the first time to solve the problem.