One of the most common attacks in the computer world are DoS attacks, a type of attack by which cybercriminals seek to prevent users of an online computer system from accessing it by flooding it with illegitimate service requests. This situation prevents legitimate users of the system from using the system and the service it provides.
Usually, these types of attacks may be aimed at affecting the source that offers the information, the application or the transmission channel of the system. If you’re already feeling lost, don’t worry as we aim to simplify the concept of a DoS attack meaning as much as possible in this article.
DoS Attack Meaning
A Denial-of-Service (DoS) attack restricts access to a computer or network in order to prevent intended users from using it. Typically, this is accomplished by overloading the target (often a web server) with a massive amount of traffic - or by sending malicious requests that cause the target resource to malfunction or crash entirely.
The first documented case of a Denial-of-Service attack was in February of 2000 when a 15-year old Canadian hacker targeted Amazon and eBay web servers with such an attack. Since then, DoS attacks have become one of the go-to tools hackers employ in order to disturb the normal operation of computer-based services and an increasing number of people have utilized DoS attacks to disrupt targets in many industries.
One of the most effective approaches to completing such an attack is through a distributed approach, which we will cover more on in a bit.
Types of DoS attacks
Some types of Denial-of-Service attacks aim to disrupt a specific target individual's access to a network or resource, while others intend to render the resource entirely inaccessible. These attacks can last anywhere from minutes to hours, and in some rare instances, even for days. These types of outages often cause major financial losses for businesses that become targets and don't have the proper mitigation strategies in place.
Denial-of-Service attacks come in many different shapes and sizes. Since not all devices and networks are vulnerable in the same ways, those trying to cause harm often have to get creative in the ways they can exploit loopholes. Following are some well-known types of Denial-of-Service exploits.
Buffer Overflow Attack
A buffer overflow attack is likely the most common type of exploit. It relies on sending more traffic to the target than developers had originally built the system to handle. This type of attack allows the bad actor to crash or even interfere with the targeted process.
ICMP Flood
An ICMP flood attack targets a misconfigured device on the target network, forcing the machine to distribute bogus packets to each and every node (computer) on the target network instead of a single node, thus overloading the network. This sort of attack may often be referred to as “the ping of death” or a “smurf attack”.
SYN Flood
An SYN flood sends a request to connect to a web server but never fully authenticates the connection. It then proceeds to target all the remaining open ports on the target web server until it forces the server to crash.
What Is A DDoS Attack?
Another similar term that you’re likely to encounter is a DDoS attack, which stands for a Distributed Denial-of-Service attack. DDoS attacks are the most common type of malware attack. In order for a DDoS attack to work, hackers introduce malware to networks of connected devices and start bombarding them with a huge amount of requests, with the intention of overwhelming the network.
DoS Vs. DDoS Attacks
The difference between a Dos and a DDoS attack is that during a DDoS attack, many malicious machines are directed to target a single resource. A Distributed Denial-of-Service attack is far more likely to be successful in disrupting the target than a DoS attack originating from a single source. Bad actors also tend to prefer this mETHod as it becomes increasingly difficult to trace the attack back to its source since the attack originates from multiple points.
Do DDoS Attacks Affect Cryptocurrencies?
As cryptocurrencies have picked up traction in recent years, crypto exchanges have become increasingly popular targets for DDoS attacks. Since 2020, there have been numerous DDoS attack attempts on some of the major crypto exchanges. This unfortunately renders the exchange’s services unavailable for a prolonged period of time. For example, when the cryptocurrency Bitcoin Gold officially launched, it immediately became the target of a massive DDoS attack that ended up disrupting their website for multiple hours.
However, the decentralized aspect of blockchains creates strong protection against DDoS and other cyber attacks. Even if several nodes fail to communicate or simply go offline, the blockchain is able to continue operating and validating transactions. When the disrupted nodes manage to recover and get back to work, they re-sync and catch up with the most recent data, provided by the nodes that were not affected.
What Is A BDoS Attack?
The rise of applications of blockchain technology has also given birth to a new type of DoS attack – a blockchain denial-of-service (BDoS) attack. These attacks focus on blockchains operating under the proof-of-work (PoW) consensus mechanism like Bitcoin.
The way this new subtype of DoS works is by attacking the rewards mechanism for miners. The PoW consensus mechanism relies on miners to validate new blocks, and if miners do not receive their rewards, block validation is interrupted. In order to interrupt the mining process, attackers send fake proofs to the blockchain that they have a mining advantage. This discourages other miners from performing operations necessary for transaction validation, which essentially slows down the processing power of the blockchain significantly.
Even so, BDoS attacks have been extremely rare and unsuccessful so far as it is important to note that it is significantly harder to perform a successful DoS attack on a decentralized network. While usually, DoS attacks rely on the centralized nature of traditional networks, this approach does not work with blockchain-based networks.
Closing Thoughts
That’s all on DoS attack meaning and their various types. Modern security technologies have developed mechanisms to defend against most forms of DoS attacks, but due to the unique characteristics of DDoS, it is still regarded as an elevated threat and is of higher concern to organizations that fear being targeted by such an attack.
Reducing them to a minimum is a primary task for not only the services provided, but also for the security and continuity of the provision of services to users.
