What is Denial of Service (DoS)?
Denial of service is a network or web service attack that seeks to maliciously engage network devices and webservers in wasteful processing and storage operations, thereby prohibiting the servicing of requests from legitimate users.
This is usually done by means of automation and involves sending a large number of requests to network endpoints/webservers at a rapid rate. This type of attack is usually carried out from a single client source and is easy to mitigate using network firewall appliances such as a web application firewall. Other advanced versions of this kind of attack include Distributed Denial of Service (DDoS), Hash DoS and DNS flooding.