Imagine you are shopping on Amazon, but suddenly the page is stuck and the page shows "Unable to access" after refreshing. Meanwhile, the backend of the enterprise is in chaos, and the technical staff is struggling to deal with the sudden traffic peak. This is not a system failure, but a well-planned DDoS attack.
In today's digital age, DDoS attacks are becoming more and more frequent and have become one of the major threats facing enterprises and individuals. It is imperative to understand its operating mechanism and take some mitigation measures.
What is a DDoS Attack?
DDoS (Distributed Denial of Service) attack is a network attack method that floods the target server with a large amount of malicious traffic, making it unable to provide services normally. Unlike traditional DoS attacks, DDoS attacks use botnets distributed around the world to launch attacks, making defense much more difficult.
The history of DDoS attacks can be traced back to the late 1990s. The earliest DoS attacks were mainly launched by a single computer, but with the development of technology, attackers began to use multiple computers to coordinate attacks, forming today's DDoS attacks.
Here are some common types of DDoS attacks:
Volumetric Attacks: Aim to exhaust the target's network resources by flooding the target's bandwidth with a large number of data packets.
Protocol Attacks: Use server connection resources by forging requests and exploiting protocol vulnerabilities to exhaust server resources.
Application Layer Attacks: Simulate normal user behavior and initiate high-frequency requests for specific applications, which are difficult to detect by traditional protection methods.
Hybrid Attacks: Combining multiple attack types increases the difficulty of defense and makes it difficult for the protection system to cope with.
How Do DDoS Attacks Work?
The core mechanism of DDoS attacks is to exhaust the resources of the target server through a large number of requests, making it unable to respond to requests from normal users. The following is a detailed operation process of DDoS attacks:
1. Building a botnet
The attacker first infects a large number of devices such as computers, mobile phones, IoT devices, etc. with malware, and these devices form a botnet after being controlled. The attacker can remotely control these devices and launch attacks in a centralized manner.
2. Launching an attack
Then, the attacker sends instructions to the botnet, and all controlled devices simultaneously send a large number of requests to the target server. These requests may be forged data packets (such as UDP Flood) or high-frequency legitimate requests (such as HTTP Flood).
3. Traffic amplification technology
Exploiting protocol vulnerabilities, attackers can amplify small traffic into huge attack traffic. First, a small DNS query request is sent, but the response returned by the server is dozens of times the size of the request, which quickly exhausts the target bandwidth.
4. Anonymous identity
The use of proxy servers or Tor networks can hide the real IP address, making it much more difficult to track attackers. In addition, the distributed nature of botnets makes it difficult to locate the source of attacks.
Why are DDoS Attacks So Common?
Low attack costs and significant effects: DDoS Attack tools are easy to obtain and the threshold for attack is low. These tools can be easily found on hacker forums, and even "on-demand attack" services are provided.
Difficult to defend: The attack sources are scattered and difficult to track. Enterprises need professional technology and equipment to mitigate attacks, which is a considerable expense for small and medium-sized enterprises.
Diverse motivations for attacks: The motivations for DDoS attacks are diverse, including economic interests, commercial competition, hacktivism, and cyber warfare. Attackers may gain market share by attacking competitors' websites, or gain economic benefits through ransomware attacks.
The Harms of DDoS Attacks
Service Interruption
DDoS attacks will cause the target system to be unable to provide services normally, and users will be unable to access websites or use services, which will directly affect the normal operation and user experience of the enterprise.
Economic Losses
Service interruption will lead to interruption of commercial transactions, and enterprises will be unable to conduct business normally, resulting in reduced revenue. In addition, enterprises need to invest a lot of time and resources to restore services and repair systems, which will also bring additional economic burdens.
Brand Damage
The unavailability of services by users will reduce their trust and satisfaction in the enterprise, thereby damaging the brand image and reputation of the enterprise. In a highly competitive market, the damage to the brand image may lead to customer loss and loss of market share.
Resource Exhaustion
DDoS attacks can cause server overload and even equipment damage. This will not only affect the normal operation of the system but may also cause hardware failure and data loss.
How to Mitigate DDoS Attacks?
1. Monitor Abnormal Traffic
In the early stages of a DDoS attack, quickly identifying abnormal traffic is the basis for attack mitigation. Abnormal traffic such as traffic surges, high bounce rates, and unexpected traffic sources usually point to the presence of bots.
Therefore, you can use some bot detection tools to analyze browser properties such as User-Agent and JavaScript execution in real time to identify whether there are some abnormal automated behaviors.
2. Technical Means to Mitigate DDoS Attacks
Once abnormal traffic is detected, measures must be taken quickly to prevent the attack traffic from further affecting the server:
Use CDN to disperse traffic
CDN (Content Distribution Network) can disperse traffic to multiple nodes to reduce the pressure on a single server. Most software CDN services on the market can not only absorb attack traffic but also route normal user requests to the nearest server through globally distributed nodes.
Deploy Web Application Firewall (WAF)
WAF protects websites from DDoS attacks by inspecting the headers and content of HTTP requests to identify and block abnormal request patterns and then filter them out to ensure that only legitimate requests reach the server.
Enable rate limiting
By setting traffic shaping and rate limiting rules, you can control the number and frequency of user requests to prevent malicious traffic from overwhelming the target system. If a user sends more than 100 requests within 1 second, the system can temporarily restrict their access, thereby effectively filtering out a large number of malicious requests.
3. Effective Prevention in the Future
Enterprises need to develop detailed DDoS attack emergency response plans, clarify the responsibilities and action steps of each department, and reduce brand property and reputation losses.
At the same time, due to the variety of DDoS attack methods, different types of malicious requests will be generated. To better deal with this situation, you can combine BrowserScan, a free browser fingerprint detection tool, to continuously monitor user behavior. It can generate a unique identifier for each visitor by analyzing multiple identification signals in the request, which can help you quickly detect abnormal behavior and take timely measures to prevent it.
Conclusion
DDoS attacks are a common network threat and are very harmful. However, after understanding the comprehensive introduction of DDoS attacks in this article, we can not only effectively resist attacks and protect our network systems and services from being affected, but also build a safer and more reliable network ecology.