DoS stands for "Denial of Service" and refers to a type of cyberattack where an attacker attempts to render a service, resource, or infrastructure inaccessible or non-functional by disrupting or interrupting normal operation. The main goal of a DoS attack is to deny legitimate users access to a service or resource by impairing the availability of the service.
There are various types of DoS attacks, including:
Volumetric Attacks: These attacks overwhelm the target with a large volume of traffic or requests to exhaust its resources and make it unreachable. An example of a volumetric DoS attack is a Distributed Denial of Service (DDoS) attack, where attackers use a multitude of compromised devices to simultaneously flood the target with traffic.
Protocol Flood Attacks: These attacks exploit vulnerabilities in network protocols to overwhelm the target's resources. An example is a SYN Flood attack, where the attacker sends a large number of TCP SYN requests without responding to them, causing the target to exhaust resources processing these requests.
Application Layer Attacks: These attacks target vulnerabilities in applications or services, attempting to crash or overload them by sending specially crafted requests or payloads. An example is an HTTP Flood attack, where the attacker sends a large number of HTTP requests to a website to exhaust its resources.
The impact of DoS attacks can be significant, including service outages, disruption of business operations, financial losses, and reputational damage. Organizations implement various measures to protect against DoS attacks, including the deployment of firewalls, Intrusion Detection and Prevention Systems (IDS/IPS), load balancers, Content Delivery Networks (CDNs), and specialized DoS protection services.