What Are DDoS Attacks? How to Prevent Them?

In today's digital world, service continuity is of great importance for both organizations and individuals. However, one of the biggest threats to this continuity is DDoS (Distributed Denial of Service) attacks. DDoS attacks aim to overwhelm targeted systems with excessive traffic, making them inaccessible. In this article, we examine in detail how DDoS attacks work, their types, impacts, and effective prevention methods.

How Do DDoS Attacks Work?

In DDoS attacks, the attacker uses thousands of compromised devices (botnets) worldwide to send simultaneous requests to the target server. The server becomes unable to handle this heavy traffic, resulting in service outages. Attacks are generally conducted by:

• Overloading servers with high-volume data traffic,
• Exploiting protocol vulnerabilities to exhaust resources,
• Slow and covert attacks at the application layer to wear down systems.

Types of DDoS Attacks

• Volumetric Attacks: Excessive bandwidth-consuming traffic is directed at the target system. Examples: UDP Flood, DNS Amplification.
• Protocol Attacks: Aim to exhaust server and network device resources. Examples: SYN Flood, Ping of Death.
• Application Layer (Layer 7) Attacks: Target web servers with seemingly legitimate traffic. Example: HTTP Flood.

Real-World DDoS Attack Examples

• GitHub Attack (2018): One of the largest DDoS attacks in history with a magnitude of 1.35 Tbps.
• Dyn DNS Attack (2016): Using the Mirai botnet, access to major websites like Twitter, Netflix, and Reddit was disrupted for hours.

Effects of DDoS Attacks

• Website and service outages,
• Financial loss and reputational damage,
• Decrease in customer trust,
• Disruption of internal network traffic and operational efficiency.

Preventive Measures Against DDoS Attacks

• Traffic Analysis Tools: Set up network monitoring systems that can detect anomalies early.
• DDoS Protection Services: Integrate CDN (Content Delivery Network) and WAF (Web Application Firewall) solutions.
• Firewall and Router Settings: Apply IP blacklists and traffic filtering policies.
• Rate Limiting: Limit requests from the same IP address to prevent overloads.
• Use of Anycast Networks: Distribute traffic geographically to minimize attack impact.
• Auto-Scalable Infrastructure: Use cloud solutions that can automatically scale capacity during traffic surges.

Crisis Management During a DDoS Attack

1. Quickly detect the event and verify it with traffic analysis tools.
2. Update firewall rules and filters to isolate the attack.
3. Contact your DDoS protection provider for support.
4. Inform your customers and users transparently.
5. Post-incident, report vulnerabilities and create an improvement plan.

Future DDoS Threats

• IoT-Based Attacks: Larger-scale botnets will be created through poorly secured devices.
• AI-Powered DDoS Attacks: Dynamic and adaptive attacks using AI techniques to bypass defenses.
• Multi-Vector Attacks: Simultaneous attacks across multiple layers (both volumetric and application layer attacks).

Being prepared against DDoS attacks involves not just technical measures but also developing crisis management plans capable of rapid action. Remember: Proactive protection is the cornerstone of cyber resilience!

• Gürkan Türkaslan
• 3 February 2021, 15:41:54