How to prevent DDoS attacks and keep your website safe

Did you know that millions of DDoS attacks occur worldwide each year, causing businesses to lose billions of dollars? These attacks don’t just target large corporations, even personal websites can become victims.

So, how to prevent DDoS attacks effectively? How can you protect your system from increasingly sophisticated threats? The following article by Douwyn will help you understand and come up with the most optimal solutions.

What is a DDoS attack?

A DDoS (Distributed Denial of Service) attack is a form of intentional cyber attack that aims to disrupt the operation of a website, server or service by overloading the system with fake traffic.

When the system cannot handle this large amount of traffic, it will slow down or stop working completely. Therefore, how to prevent DDoS attacks is one of the important issues that businesses need to pay attention to in order to protect their network systems.

What is a DDoS attack?

How does a DDoS attack work

A DDoS attack works by taking advantage of a network of infected computers (botnets) to send a large number of requests to the target server. When the number of requests exceeds the system’s processing capacity, the service will be interrupted.

To ensure safety, security experts recommend applying DDoS attack prevention measures such as using firewalls, CDNs, or advanced security solutions.

How DDoS attacks work

Consequences of DDoS attacks

DDoS attacks can cause many serious damages:

• Service disruption: Websites cannot be accessed, affecting customers and revenue.

• Financial losses: E-commerce businesses can lose millions of dollars due to system downtime.

• Brand reputation loss: Customers can lose trust if the website is down continuously.

• Security risks: Some DDoS attacks can be used to hide other attacks.

Due to the dangerous level of these attacks, businesses need to equip themselves with knowledge about how to prevent DDoS attacks and implement appropriate measures to protect their systems. A comprehensive security strategy will help minimize risks and ensure stable operation for the website.

In the following sections, we will learn in detail about methods of preventing DDoS attacks, helping businesses and individuals to proactively prevent this threat effectively.

Common types of DDoS attacks

Understanding the types of DDoS attacks is the first step to building an effective DDoS attack prevention method. Each type of attack has its own operating mechanism, requiring different protection methods. Below are the three most common groups of DDoS attacks that businesses and network administrators need to pay attention to when implementing DDoS attack prevention methods.

Volumetric Attacks

Volumetric Attacks are the most common form of attack, in which hackers use botnets to send a large amount of fake data to the target, consuming the entire bandwidth of the system. When the resources are used up, the website or server will not be able to respond to requests from legitimate users.

Common forms of attack

• UDP Flood: Send a series of UDP packets to random ports on the server, causing the system to check continuously and consume resources.

• ICMP Flood (Ping Flood): Send continuous ping packets to the server to exhaust the bandwidth.

• DNS Amplification: Take advantage of public DNS servers to send a large amount of responses to the target, causing overload.

• NTP Amplification: Use vulnerabilities in the NTP server to amplify the attack traffic.

How to prevent volumetric DDoS attacks

• Increase bandwidth: Help the system to be more resistant to sudden traffic.

• Use firewalls and packet filters: Block invalid packets from UDP, ICMP.

• Configure request restrictions: Limit the number of requests from an IP in a certain period of time.

• Use Anycast Network & CDN: Distribute traffic to reduce the load on the main server.

• Apply specialized anti-DDoS services: Such as Cloudflare, AWS Shield, Akamai.

Volumetric Attacks

Protocol Attacks

Protocol Attacks exploit vulnerabilities in network protocols to drain system resources. The main targets are connection handlers on servers, firewalls, or load balancers.

Common Attack Types

• SYN Flood: Hackers send a series of SYN connection requests but do not complete the capture processTCP hand, exhausting the server’s resources.

• Ping of Death: Send ICMP packets that are too large, causing buffer overflow and system crash.

• Smurf Attack: Use fake IP addresses to send ICMP packets to many devices at the same time, overloading the target.

• ACK Flood: Send a series of ACK packets (ACKnowledgment) to make the server process continuously, overloading the CPU.

How to prevent protocol-type DDoS attacks

• Configure firewalls to block abnormal traffic.

• Apply intrusion detection and prevention systems (IDS/IPS) to filter malicious traffic.

• Limit the number of open connections (Connection Limiting) to prevent SYN Flood.

• Enable SYN Cookies to authenticate valid connection requests.

• Redirect DDoS traffic to Blackhole Routing to reduce the load on the system.

Application Layer Attacks

Application Layer Attacks target web applications instead of network infrastructure. This is the most sophisticated form of attack, as it simulates legitimate access behavior, causing the server to process a large number of requests without being able to distinguish between real users and attackers.

Common Attack Types

• HTTP Flood: Sends a series of GET or POST requests to the web server to overload the CPU and memory.

• Slowloris: Keeps the HTTP connection open for as long as possible, causing the server to run out of connection resources.

• Zero-Day DDoS Attacks: Exploits new unpatched vulnerabilities to carry out attacks.

• XML-RPC Pingback Attack: Takes advantage of blogs or websites with XML-RPC features to amplify attacks.

How to prevent Application Layer DDoS attacks

• Use Web Application Firewall (WAF): Helps filter abnormal requests.

• Rate Limiting: Limit the number of requests from an IP within a certain period of time.

• Use CAPTCHA: Require users to authenticate to prevent automated bots.

• Optimize server performance: Use caching to reduce the load on the web server.

• Deploy AI & Machine Learning: Helps detect sophisticated attack patterns.

Application Layer Attacks

How to effectively limit DDoS attacks

DDoS attacks are increasingly sophisticated and can cause serious damage to websites, network systems and businesses. To protect your system, you need a solid defense strategy. Below are effective ways to prevent DDoS attacks that you should apply.

Strengthen network infrastructure security

One of the important measures to combat DDoS attacks is to ensure that the system has good load-bearing capacity.

• Expand bandwidth: Helps the system handle high traffic without being overloaded.

• Load Balancer: Distribute traffic across multiple servers to avoid over-concentration on a single point.

• Use a dedicated DDoS protection service: Platforms like Cloudflare, AWS Shield can help absorb attack traffic.

Use protection technology

Security tools help detect and block malicious traffic before it affects the system.

• Firewall and Intrusion Detection System (IDS/IPS): Helps filter invalid packets and block suspicious access.

• Web Application Firewall (WAF): Prevents application layer attacks like HTTP Flood, SQL Injection.

• Rate Limiting: Limits the number of requests from an IP to prevent spam request behavior.

How to effectively mitigate DDoS attacks

Use a content delivery network (CDN)

Distribute traffic: CDNs help reduce the load on the main server by storing data on multiple global servers. Prevent volumetric attacks: By absorbing traffic from many different sources, CDNs can reduce the effectiveness of attacks. Monitor and respond promptly Traffic monitoring: Use tools like Datadog, New Relic to detect abnormalities. Activate emergency protection mode: When an attack is detected, it is necessary to quickly activate temporary blocking measures. Have a response plan: Preparing scenarios in advance helps reduce response time when incidents occur.

Use anti-DDoS support tools

To protect your website and network from DDoS attacks, using specialized security tools is essential. Below are some popular anti-DDoS solutions that help minimize risks and ensure stable system operation.

Comprehensive protection solutions

Services such as Cloudflare, AWS Shield, Google Cloud Armor provide multi-layered DDoS protection, from content delivery networks (CDNs) to web application firewalls (WAFs).

These platforms not only help prevent DDoS attacks but also enhance website performance by distributing traffic.

Monitoring and early detection tools

MonitoringNetwork traffic helps detect anomalies before a DDoS attack occurs. Platforms like Imperva, Akamai Kona Site Defender use AI to analyze user behavior, helping to automatically identify and block malicious traffic.

Protect websites and web applications

For small websites and CMS platforms like WordPress, Magento, Sucuri is a popular choice. This tool provides a web application firewall (WAF) and security monitoring system, helping to prevent not only DDoS attacks but also other threats such as malware and SQL Injection attacks.

Conclusion

In the context of increasingly sophisticated cyber attacks, no business or individual is immune to DDoS. Investing in security solutions not only helps protect websites but also ensures sustainable development for businesses. Take the initiative to prevent DDoS attacks now to avoid unnecessary risks in the future.

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