Which of the following DDoS attacks overloads a service by sending inundate packets?

Distributed Denial of Service (DDoS) attacks are broadly classified based on the network layer they target. A network-centric attack, also known as a volumetric attack, aims to consume the available bandwidth of the target's network connection or the processing capacity of network equipment. It achieves this by "inundating" the target with a massive volume of packets, such as in UDP or ICMP floods. This method directly overloads the network infrastructure, making the service unavailable to legitimate users.

B. An application-centric attack targets Layer 7, exhausting server resources (CPU, memory) with seemingly legitimate but resource-intensive requests, not necessarily by packet volume.
C. A web-centric attack is a specific type of application-centric attack that targets web servers and applications, such as with HTTP floods.
D. System-centric is not a standard classification for DDoS attacks. The primary categories are network-centric (volumetric/protocol) and application-centric.

1. Zargar, S. T., Joshi, J., & Tipper, D. (2013). A survey of defense mechanisms against distributed denial of service (DDoS) flooding attacks. IEEE Communications Surveys & Tutorials, 15(4), 2046-2069. https://doi.org/10.1109/SURV.2013.031413.00014. Section II.A, "Classification of DDoS Flooding Attacks," categorizes attacks, describing bandwidth depletion (volumetric) attacks as a primary type that inundates the victim's network.

2. Lau, F., Rubin, S. H., Smith, M. H., & Trajkovic, L. (2000). Distributed denial of service attacks. IEEE International Conference on Systems, Man, and Cybernetics, 3, 2275-2280. This foundational paper describes DDoS attacks as efforts to "exhaust the resources of a remote host or network" through packet flooding.

3. Imperva. (n.d.). Network Layer DDoS Attacks. Official Vendor Documentation. This document defines network layer (OSI Layers 3 & 4) attacks as those that "inundate a server with an overwhelming amount of traffic," which corresponds to the network-centric classification.