What's the limiting resource that makes DDoS attacks possible?

Question

I often see DDoS attacks compared by network traffic, for example:

The biggest DDoS attack to date took place in February of 2018. This attack targeted GitHub, a popular online code management service used by millions of developers. At its peak, this attack saw incoming traffic at a rate of 1.3 terabytes per second (Tbps), sending packets at a rate of 126.9 million per second.

Source: https://www.cloudflare.com/learning/ddos/famous-ddos-attacks/

But is that really the problem? Clogging up the network?

Or is it processing power, RAM, or something else?

Answer 1

Distributed Denial of Service is a type of DoS attack where multiple compromised systems target the resources of a single system to bring it offline. The resources can be any of those you stated and they mostly fall into one of these categories:

Traffic attacks: Traffic flooding attacks send a huge volume of TCP, UDP and ICPM packets to the target. Legitimate requests get lost and these attacks may be accompanied by malware exploitation.

Bandwidth attacks: This DDos attack overloads the target with massive amounts of junk data. This results in a loss of network bandwidth and equipment resources and can lead to a complete denial of service.

Application attacks: Application-layer data messages can deplete resources in the application layer, leaving the target's system services unavailable.