Final answer:
A Denial of Service (DoS) attack aims to disrupt a computer system or network by flooding it with requests, which can cause slowdowns or stoppages. DDoS, a variant involving multiple systems, also poses significant threats to service availability. Effective cybersecurity measures are essential for protection.
Step-by-step explanation:
A Denial of Service (DoS) attack attempts to slow down or stop a computer system or network by flooding a computer or network with requests for information and data. These requests can overwhelm the system, depleting its resources and making it difficult or impossible for legitimate users to access services. In some cases, these attacks are carried out by multiple compromised systems, in a coordinated fashion, which is referred to as a Distributed Denial of Service (DDoS) attack. DoS and DDoS attacks are significant threats to the availability of online services, and combating them requires a combination of cybersecurity measures including firewalls, intrusion detection systems, and properly configured network architecture.