What is a common characteristic of a DDoS attack?

A common characteristic of a Distributed Denial of Service (DDoS) attack is that it overwhelms a service with excessive traffic. The fundamental goal of a DDoS attack is to make a targeted online service unavailable to its intended users by flooding it with an overwhelming amount of requests. This can exhaust the resources of the targeted system, such as bandwidth, memory, or processing power, leading to slowdowns or complete outages.

In contrast, the other options describe different types of attacks or goals. For instance, stealing data from databases pertains to data breaches or exfiltration techniques, which are fundamentally different from the objectives of a DDoS attack. Encrypting files for ransom refers to ransomware attacks, which focus on restricting access to data until a ransom is paid. Targeting individual users typically involves different tactics, such as phishing or malware campaigns, which also do not align with the mass bombardment strategy characteristic of DDoS attacks. Thus, option B accurately captures the essence of a DDoS attack's operational mechanism.