What characterizes a DDoS attack?

A Distributed Denial of Service (DDoS) attack is characterized by flooding a target network or service with an overwhelming amount of traffic originating from multiple compromised devices, often referred to as a botnet. This surge in traffic can lead to service disruption, making it difficult or impossible for legitimate users to access the targeted service or network.

In this context, the other choices do not align with the defining characteristics of a DDoS attack. For example, physical access to a network pertains to unauthorized entry, which is not a feature of DDoS as it relies on remote, coordinated traffic generation from many devices. Social engineering typically involves manipulation techniques to acquire sensitive information or access credentials rather than using bulk traffic. Meanwhile, data encryption for ransom relates to ransomware attacks, which encrypt files and demand payment for decryption, differing fundamentally from the traffic-based disruption seen in DDoS attacks. Thus, the hallmark of a DDoS attack is indeed the simultaneous flooding of requests from numerous compromised systems targeting a single resource.