Jason is monitoring his network and notices that hundreds of different IP addresses are sending requests to one of his organization's servers. The requests are small, and when he inspects them he sees a simple HTTP GET command for a file. When the server responds, it sends back a very large response. What type of attack is likely occurring, and what is it attempting to accomplish?

This is most likely a distributed denial-of-service (DDoS) attack since it is coming from many different IP addresses. Using small requests to generate large responses is an example of a resource exhaustion attack. Since this is coming from many addresses rather than one or a small number, it is more properly called a DDoS than a simple denial-of-service (DoS) attack. There is no indication that the service is vulnerable, the requests are small and no mention is made of a specific payload other than a HTTP GET for a file, and there is no traffic redirection as you would expect in an on-path attack.