In the recent past, DoS attacks were performed by individuals, using the physical resources of one or a handful of computers. This was primarily because of a lack of technical know-how to perpetrate large scale attacks. Gradually, easy-to-use utility programs evolved which made performing DoS attacks easier. This lead to an increase in the occurrences of DoS attacks. The surge in DoS attacks was especially notable with many web-based companies being targeted. These included major websites such as Amazon, Ebay!, and Microsoft.
DoS attacks evolved further with the usage of tools, which perpetrate attacks generated by malware. Once installed, the malware would direct the infected machine to attack specific targets. If multiple infected computers targeted the victim simultaneously, the effects of the attack were greatly amplified.
The next evolution of DoS saw the attackers develop botnets, which are a centrally managed network of compromised computers. This followed the upsurge in DDoS attacks. In a DDoS attack, an attacker uses multiple machines to launch an attack. The internet saw the invention or refinement of techniques to bring computers under the attackers' control and to produce powerful attacks. DoS attacks are the most significant threat in the online world today, especially for businesses which depend on web-based transactions.