Denial of Service attacks aim to disrupt which aspect of network functionality?

Denial of Service (DoS) attacks are primarily designed to disrupt authorized operations by overwhelming a network or system, making it inaccessible to legitimate users. When a DoS attack is executed, the attacker typically floods the target with excessive requests or traffic, exhausting resources and causing legitimate requests to be dropped or delayed. This results in authorized users being unable to perform their intended actions or access the services they need.

In the context of the options provided, focusing on authorized operations highlights the core intention of DoS attacks: to obstruct the normal functionality of services that users depend on, ultimately leading to denied access to those services. This disruption is particularly critical in environments where constant availability and operational continuity are crucial.

The other options, such as network bandwidth, data integrity, and user authentication, while they may see secondary effects during a DoS attack, are not the primary focus. The attack's goal is not necessarily to manipulate bandwidth directly, compromise data integrity, or bypass user authentication, but rather to ensure that the services themselves become unavailable for legitimate users.