To effectively protect against DDoS (Distributed Denial of Service) attacks, it is crucial to understand how they work. Unlike a simple overload caused by a spike in legitimate traffic, a DDoS attack is a malicious action, planned and orchestrated from multiple locations around the world. It aims to make an online service—website, application, server, etc.—unavailable or unstable by saturating it with artificial requests.
The principle is based on the multiplication of attack sources. Rather than coming from a single computer, the data flow is generated by thousands or even millions of devices around the world. This distributed dimension makes detection and neutralization much more complex than for a traditional DoS (Denial of Service) attack, which originates from a single machine.
DDoS attacks can target different points in a system: network bandwidth, system resources (CPU, memory), or even the applications themselves. Some aim to saturate TCP connections, while others exploit protocol vulnerabilities (DNS, HTTP, etc.) to maximize their impact. Depending on the objective, an attack can last from a few minutes to several days, with potentially major economic and reputational consequences for the targeted organization.
The Crucial Role of Botnets
At the heart of most DDoS attacks are botnets, networks of compromised devices controlled remotely by cybercriminals. A botnet consists of a multitude of devices connected to the Internet: personal computers, servers, smartphones, connected objects (IP cameras, thermostats, voice assistants, home routers, etc.). These devices are infected without their owners’ knowledge, usually via malware spread by email, malicious downloads, or by exploiting unpatched security vulnerabilities.
Once integrated into the botnet, these devices become “bots” (or ‘zombies’), obeying the instructions of their master, often called a “bot herder” or botnet operator. The operator can, at any time, launch a DDoS attack by commanding the entire network to send massive, simultaneous data packets to a specific target.
This avalanche of traffic exceeds the processing capacity of the targeted server, which ends up being unable to respond to legitimate requests. The result: extreme slowdown, loading errors, or complete service outage. For the end user, this means being unable to access the site, customer service being unavailable, or transactions being interrupted.
Why are these attacks so dangerous?
Several factors make DDoS attacks a formidable threat:
-Difficulty identifying sources: requests come from ordinary devices scattered around the world, making it difficult to filter them without impacting legitimate users.
-Flexibility of attack modes: cybercriminals can adapt their methods to the target (volumetric, application-based, protocol-based, or mixed).
-Ease of access: Illegal DDoS-as-a-Service offerings are now available on the dark web, allowing anyone to launch an attack without any particular technical expertise.
-Collateral effects: An attack can impact not only the direct target, but also ISPs, hosting providers, and end users connected to the same infrastructure.