What is a DDoS attack?

In May 2017, WannaCry ransomware affected more than 230,000 devices in 150 countries. This attack encrypted data on infected computers, demanding a ransom for recovery. In 2013, a cyberattack compromised three billion Yahoo user accounts, in a case that took years to detect. These examples are just a sample of how companies face increasing vulnerability in the digital environment.

Today, companies operate globally and are interconnected through the network, generating much of their revenue through online platforms. However, this virtual expansion comes with significant challenges. One of the most common and disruptive types of attacks is the DDoS (Distributed Denial of Service) attack.  This type of attack takes advantage of specific capacity limits that apply to any network resource, such as the infrastructure that enables the organization's website.

Common targets of DDoS attacks include:

1. Online shopping sites.

2. Online casinos.

3. Companies or organizations that depend on the provision of online services.

   
   

How does a DDoS attack work?

Network resources have a finite limit of requests they can serve at the same time. These networks are made up of computers and other devices (such as IoT devices) that have been infected with malware, allowing an attacker to control them remotely.

These individual devices are called bots or misnamed (zombies), and a group of bots is called a botnet.

The attacker's intention is to completely prevent the normal operation of web resources, a total “denial” of service. The attacker requests a payment to stop the attack. In some cases, the goal of the DDoS attack may be to discredit or harm a competitor's business.

Using botnet “zombie network” to launch a DDoS attack

To send a large number of requests to the victim, the attacker often establishes a “zombie network” of infected computers. As the attacker controls the actions of each infected computer in the zombie network, the attack can overwhelm the victim's web resources.

How to Identify a DDoS Attack

One of the first signs of a DDoS attack is a site slowdown or lack of access to a service. However, it is important to remember that these performance issues can also be caused by a legitimate increase in traffic, so a thorough investigation is necessary. Traffic analysis tools can be of great help in identifying warning signs, such as the following:

• Suspicious traffic from a single IP or range of IPs: An unusually high volume of traffic coming from the same IP address or a specific range can be a red flag.

• Similar behavior between users: If much of the traffic is seen to be coming from users who share similar characteristics (such as device, geographic location, or browser version), this could indicate a coordinated action typical of an attack.

• Sudden increase in requests to a specific page: An unexplained increase in requests to a single page or server resource can be another sign of an attack.

• Unusual traffic patterns: Traffic spikes at unusual times or repetitive patterns (such as increases in traffic every 10 minutes) can also be signs of a DDoS attack.

There are other more specific signals that can vary depending on the type of DDoS attack; Therefore, it is essential to constantly monitor traffic to detect anomalies and act quickly in the event of an attack.

How to protect against DDoS attacks

Protecting against DDoS attacks is essential for any organization. Here are some strategies that can be implemented:

1. Constant monitoring: Implement network monitoring tools that can detect unusual traffic or patterns that suggest a DDoS attack.

2. Increased bandwidth capacity: Although it does not prevent attacks, having more bandwidth can help absorb additional traffic during an attack.

3. Implementing DDoS solutions: There are DDoS mitigation services that can help filter malicious traffic before it reaches the server.

4. Redundancy and distribution: Using content delivery networks (CDN) and load balancing solutions can help distribute traffic and mitigate the impact of an attack.

5. Incident response plan: Having a clear and defined plan for how to react to a DDoS attack can help minimize the impact and speed recovery.

Most Common Types of DDoS Attacks

There are several DDoS attack vectors that focus on different parts of a network connection. To understand how these attacks operate, it is essential to know how a network connection is established on the Internet and its multiple layers.

A network connection is built on several elements or "layers", each with a specific function, similar to the foundation and floors of a house. These layers are described in the OSI model, a conceptual framework that divides a connection into seven layers, from the physical layer (most basic level of data transmission) to the application layer (where users interact with applications).

OSI model.

In many cases, attackers combine multiple attack vectors or alternate them in response to the defense measures implemented by the victim, creating sophisticated and difficult to mitigate DDoS attacks.

The distributed nature of DDoS attacks, combined with the use of a large number of compromised devices, makes them one of the most difficult threats to mitigate in the field of cybersecurity. The best defense is to be prepared with adequate security measures and an incident response plan.