A Distributed Denial-of-Service (DDoS) attack is a cybercrime where attackers flood a server with internet traffic, preventing users from accessing connected online services and sites. DDoS attacks utilize botnets and target various network layers, including application, protocol, and volume-based attacks, causing financial losses, operational disruption, and reputational damage.

Types of DDoS Attacks

DDoS attacks can be categorized into different types based on the OSI model layers they target. These attacks aim to disrupt services by overwhelming the target with internet traffic, exploiting weaknesses in network layers, or consuming available resources. The main types of DDoS attacks include:

• Volume-based or volumetric attacks: Control all available bandwidth between the victim and the larger internet.

• Protocol attacks: Exploit weaknesses in Layers 3 and 4 of the OSI protocol stack, consuming all available capacity of web servers or other resources, such as firewalls.

• Application-layer attacks: Target the layer where web pages are generated on the server in response to HTTP requests, aiming to exhaust or overwhelm the target's resources.

• Amplification attacks: Send requests to a DNS server with a spoofed IP address, causing the target to receive a large volume of unsolicited responses.

Signs of a DDoS Attack

Recognizing the signs of a DDoS attack is crucial for timely mitigation and prevention of potential damage. Some common indicators of a DDoS attack include:

• Unusual traffic spikes: Sudden increases in network traffic that deviate from normal patterns.

• Slow performance: Unexplained sluggishness in accessing websites or online services.

• Intermittent connectivity: Frequent disconnections or difficulty connecting to online resources.

• Excessive resource consumption: High CPU or memory usage without a clear cause.

Preventing DDoS Incidents

Preventing DDoS incidents involves a combination of proactive measures and robust security solutions. Regular risk assessments help identify network vulnerabilities, while traffic analysis differentiates between legitimate and malicious traffic. Employing advanced firewall protection, such as Web Application Firewalls (WAFs), can filter out malicious traffic and protect against application-layer attacks.

Another effective strategy is using Anycast network distribution to distribute attack traffic across multiple servers, mitigating the impact. Planning for capacity, such as scaling resources or using cloud-based DDoS protection services, ensures that infrastructure can handle traffic spikes and maintain service availability during an attack.

Mitigating the Impact of DDoS

Mitigating the impact of DDoS attacks involves a combination of strategies and tools:

• Risk assessment: Identifying network vulnerabilities and potential threats.

• Traffic differentiation: Distinguishing between legitimate and malicious traffic.

• Black hole routing: Redirecting malicious traffic to a "black hole" to protect the target.