What Is a Distributed Denial of Service (DDoS) Attack? How Does It Work?

As online businesses and services grow, so do the threats to their stability and security. One of the most disruptive cyberattacks businesses face today is the Distributed Denial of Service (DDoS) attack.

Unlike a traditional Denial of Service (DoS) attack, which comes from a single source, a DDoS attack leverages a distributed network of devices to flood a target with traffic. The result can be severe: downtime, financial loss, and a damaged reputation.

This article explores the mechanics of a DDoS attack, why they happen, and what businesses can do to protect themselves.

What Is a DDoS Attack?

A Distributed Denial of Service (DDoS) attack is a type of cyberattack that aims to disrupt the normal functioning of a server, service, or network by overwhelming it with an enormous volume of traffic. Unlike a DoS attack, which originates from a single source, a DDoS attack comes from multiple sources—often hundreds, thousands, or even millions of compromised devices worldwide.

These devices, collectively known as a botnet, act on behalf of the attacker to bombard the target, ultimately crashing or severely slowing down the service.

The core objective of a DDoS attack is to exhaust the target’s resources—bandwidth, memory, or processing power—so legitimate users are unable to access the service. DDoS attacks often require no advanced hacking skills, as attackers can buy “DDoS-for-hire” services on the dark web, making it an accessible form of cyber assault for various motives.

How Does a DDoS Attack Work?

A DDoS attack generally involves three main steps:

• Botnet Creation: The attacker first creates or rents a botnet, a network of infected devices (computers, smartphones, IoT devices) that have been compromised with malware. These devices are often part of the attack unknowingly.
• Attack Coordination: Once the botnet is ready, the attacker instructs it to send a massive number of requests or data packets to the target. Since these requests come from multiple sources (spread across the botnet), they appear legitimate, making it difficult for defenses to distinguish between real and malicious traffic.
• Resource Exhaustion: As the botnet floods the target with traffic, the server’s resources are overwhelmed, leading to a slowdown or complete crash. This results in legitimate users being unable to access the service until the attack subsides or is mitigated.

Common Types of DDoS Attacks.

DDoS attacks can be classified into several categories based on how they overload a target:

• Volumetric Attacks: These attacks flood the target with a high volume of traffic, overwhelming its bandwidth. For instance, UDP floods (User Datagram Protocol) send massive quantities of data packets to the target’s network to consume available bandwidth and render the service inaccessible.
• Protocol Attacks: Also known as state-exhaustion attacks, these target server resources by exploiting protocols. For example, a SYN flood attack exploits the TCP handshake process by sending multiple connection requests without completing them, ultimately exhausting server resources.
• Application Layer Attacks: These attacks target specific applications on the server rather than the network as a whole. HTTP floods, for example, involve sending a large number of seemingly legitimate HTTP requests to a web server, overwhelming the application layer and causing it to crash.

Why Do DDoS Attacks Happen?

DDoS attacks are motivated by a variety of reasons, including:

• Financial Gain: Attackers may use DDoS attacks as part of an extortion scheme, demanding ransom in exchange for stopping the attack. This is often referred to as a “DDoS ransom attack.”
• Competitor Sabotage: Some DDoS attacks are initiated by competitors aiming to disrupt a business’s online presence during a crucial period, such as a product launch or holiday season.
• Hacktivism: Groups with ideological motives, known as hacktivists, may use DDoS attacks to target organizations they oppose politically, socially, or environmentally.
• Revenge and Malice: Sometimes, disgruntled employees, unhappy customers, or malicious actors launch DDoS attacks to harm a company or individual as a form of retaliation.

Impact of a DDoS Attack.

A successful DDoS attack can have significant consequences for a business:

• Downtime and Revenue Loss: For e-commerce platforms, financial institutions, and SaaS providers, any downtime means lost revenue and customer dissatisfaction. Prolonged downtime can damage customer trust and lead to revenue losses.
• Brand Damage: A company that suffers frequent or extended service outages due to DDoS attacks may see its reputation suffer. Customers may question the reliability and security of the service, which can impact long-term loyalty.
• Increased Security Risks: In some cases, a DDoS attack can act as a diversion while other cyber threats, like data breaches or malware infections, target the organization. With resources focused on mitigating the DDoS, other vulnerabilities may be left exposed.

How to Defend Against DDoS Attacks?

While completely preventing DDoS attacks is challenging, there are strategies and tools that can reduce their impact:

• Rate Limiting and Traffic Filtering: Implementing rate limits and filtering out suspicious traffic can help manage incoming requests, minimizing the strain on servers.
• DDoS Protection Services: Cloud providers and specialized security services offer DDoS protection, which helps absorb and redirect malicious traffic away from the target server.
• Load Balancers: Load balancers can distribute incoming traffic across multiple servers, preventing any single server from becoming overwhelmed and minimizing the impact of a DDoS attack.
• Geolocation and IP Blocking: Blocking or filtering IPs from regions that are not relevant to the business can reduce potential attack surfaces.
• Intrusion Detection Systems (IDS): An IDS can help detect unusual traffic patterns early, allowing companies to respond quickly to potential DDoS activity.

Responding to a DDoS Attack.

In the event of a DDoS attack, businesses should take the following steps:

• Identify and Analyze the Attack: Determine the type and scale of the attack. This information can help in deciding the best response strategy.
• Engage with ISPs and Security Partners: Some ISPs offer DDoS protection and can help divert or limit malicious traffic.
• Communicate with Customers: If the attack is affecting user access, keeping customers informed can prevent unnecessary frustration and maintain transparency.
• Prepare for Future Attacks: After the attack, analyze what happened and adjust security measures to be better prepared for future attacks.

Conclusion: Staying Resilient in the Face of DDoS Threats.

DDoS attacks are a significant threat in today’s cyber landscape, impacting businesses large and small. Although preventing them entirely may not be possible, understanding the nature of these attacks and taking proactive security measures can help businesses minimize the impact and maintain a stable online presence.

Building a DDoS response strategy, using robust protection tools, and constantly monitoring traffic for suspicious activity can be the difference between minor disruptions and severe, costly downtime.

By staying prepared, businesses can protect themselves from the damaging effects of DDoS attacks and maintain trust with their customers.