What is the difference between a DoS attack and a DDoS attack, and why should crypto investors be aware of it?

Internet security is a critical issue today, especially when it comes to protecting digital assets. One of the most common security threats is attacks known as DoS and DDoS. Although both terms are often used interchangeably, they refer to two distinct threats with different impacts and characteristics.

Basic Principle of DoS Attack

A DoS attack (Denial-of-Service) means a targeted disruption of the availability of a service or network. The attacker overloads the server with a massive volume of data or sends a large number of malicious requests, causing the server to become unavailable to legitimate users. This is a method that has been used since the early 2000s when a 15-year-old Canadian hacker attacked the servers of large e-commerce companies, demonstrating the vulnerability of online infrastructure.

Although DoS attacks may seem simple, there are various variants of them. Each focuses on a different aspect of network communication and infrastructure. The duration of these attacks ranges from minutes to several days, depending on the chosen type and strength of the attack.

Main Types of DoS Attacks

Buffer overflow is one of the most common variants. The attacker sends more data than the server was prepared for. This causes overload, process failure, or complete outage.

ICMP flood targets poorly configured devices on the network. The attacker forces them to send packets to all nodes instead of just one, thereby clogging the network with unnecessary traffic. This method is often referred to as “ping of death.”

SYN flood works by having the attacker initiate a connection to the server but never fully verifies it. Instead, it gradually targets all available ports, causing them to fail over time.

DDoS attack – a distributed and more powerful variant

The fundamental difference between a DoS and a DDoS attack lies in their scope. While a DoS attack originates from a single source, a DDoS (Distributed Denial-of-Service) attack is launched simultaneously from many different sources. This means that the attacker controls a network of compromised devices (botnet) and coordinates their actions against a single target.

This distribution of attacks also explains why DDoS attacks are more effective and harder to stop. Their source is more difficult to trace, and thus they have become the number one method for malicious actors. Common defense systems designed against a single source of traffic prove ineffective here.

Cryptocurrency Exchanges in Danger

In recent years, cryptocurrency exchanges have increasingly become targets of these attacks. This is not surprising – every outage of an exchange has financial consequences for operators and users. An emblematic example is the attack on Bitcoin Gold shortly after its launch, when a DDoS attack took the network's website down for several hours.

Similar incidents have also occurred with other projects and exchanges, which has heightened the need for more robust protection. In general, web servers are not the only targets – any devices connected to the internet can come under the attackers' radar.

How Blockchain Defends Against Attacks

Although exchange websites are at risk, the blockchain itself has strong protection against these attacks. Its decentralized architecture serves as a natural barrier.

If some nodes are unavailable or offline, the network continues to operate without interruption. Transactions are verified normally, and once the affected nodes return to the network, they synchronize with the latest information.

Bitcoin, as the oldest and largest blockchain, demonstrates the highest level of resilience. Due to the high number of nodes and enormous hash rate, it is practically impossible for any attack to significantly disrupt the network.

Technical Guarantees and Their Strength

The proof-of-work mechanism in Bitcoin ensures that all data on the network is protected by cryptographic proofs. Verified blocks are practically immutable. For someone to attempt to modify past transactions, they would have to crack the entire history of the blockchain, which is impractical even for the most powerful computers.

Theoretically, an attacker could achieve this by controlling more than 50% of the hash rate (51% attack), but even then, they could only influence the last few blocks. Such an attack would be quickly detected, and the community would immediately update the protocol for defense.

In conclusion, while exchange servers must be protected against DDoS attacks using traditional methods, the blockchain itself has built-in mechanisms that make it very resilient to such attacks.