What is a denial-of-service attack (DoS)?

A DoS attack is a method of harm in cyberspace. The essence is simple. Someone maliciously overloads a server or website, and it stops working. Ordinary users suffer — there is no access.

The first such case? February 2000. A teenager from Canada, just 15 years old, attacked the giants — Amazon and eBay. Since then, these attacks have become a popular weapon. For chaos. For trouble.

Types of DoS Attacks

There are different types of DoS. Sometimes one user is blocked, sometimes an entire resource. Minutes, hours, days… The duration is unpredictable. Financial losses? Huge. Especially for the unprepared.

The forms of attacks are changing. The attackers are inventive. They look for weaknesses. And they find them.

Main types of DoS attacks:

Buffer overflow attack

The most common. The principle seems simple — send more data than the system can handle. The result? Control over processes or blocking.

ICMP flood

“Death ping” — that's what it's also called. Or “smurf attack”. A misconfigured device starts sending fake packets throughout the network. Overload is inevitable.

SYN-flood

Imagine: someone knocks on the door and runs away. Knocks again. And runs away again. The server tries to respond to connection requests, but the process never completes. The ports are open. The system crashes.

DoS Attacks Compared to DDoS Attacks

DDoS is DoS on steroids. Instead of one source of attack, there are many. From all sides at once. Effective. Difficult to trace. That's why hackers love it.

The Impact of DoS Attacks on Cryptocurrencies

Usually, large companies suffer. Banks. Stores. Government institutions. But in reality, anyone who is online can be at risk.

Cryptocurrencies also attract attention. Here's an example: Bitcoin Gold was launched, and a few minutes later — bam! DDoS attack. The site was down for hours.

But blockchains… they are an interesting thing. Decentralization is their shield. Some nodes go down? No problem. The network lives on. Transactions continue. The fallen nodes rise and synchronize with the live ones.

The more nodes and hash rate, the stronger the protection. Bitcoin seems to be the most secure. It is old. It is popular. It is resilient.

Proof of Work — another layer of protection. It is nearly impossible to change what has been recorded. Even the most powerful computers cannot handle it.

Even if the attack is successful, the impact will be minimal. A few blocks. A short time. And what if someone suddenly gains control of 51% of the network? The protocol will be updated. The protection will be strengthened. Bitcoin is resilient. It seems so.