Final answer:
A DoS or DDoS attack occurs when a network or a system is intentionally overwhelmed with traffic to disrupt its normal functions. These attacks can cause significant damage to both general and specialized digital infrastructures, such as those involved in nuclear power plant operations.
Step-by-step explanation:
An attack as described occurs when a system is overwhelmed by excessive data, rendering it incapable of performing its intended functions. This is commonly referred to as a Denial-of-Service (DoS) attack or, if it is carried out by multiple systems, a Distributed Denial-of-Service (DDoS) attack. These attacks can target varied digital infrastructures, ranging from individual websites to extensive networks, and their disruptive potential is significant.
Essentially, a DoS attack works by inundating a target with more traffic than it can handle, which can cause systems to slow down or crash entirely. This might be achieved through various methods, such as sending numerous requests to load a webpage or exploiting software vulnerabilities. DDoS attacks are an extension of this concept but conducted from a multitude of compromised computers controlled by an attacker. This makes the assault more difficult to mitigate as the traffic originates from a range of locations and IP addresses.
Additionally, the risks to specialised systems, such as those of nuclear power plants, are noteworthy. A technological failure induced by natural disasters, like the earthquake that struck Fuushima, or a targeted systematic attack, can have dire consequences.