A Yo-Yo attack is a type of DDoS attack where hackers exploit the features that cloud services provide to attack organizations. The target organizations have usually signed up to use one of the available cloud services. Cloud services provide a reactive auto-scaling feature via load balancer systems. Hackers exploit this by increasing the volume of junk traffic over a period of time.
Yo-Yo attacks have become important because hackers are using Yo-Yo attacks to target more and more websites. If the website owners and network administrators along with cloud service providers do not take the necessary security measures against Yo-Yo attacks, hackers will likely cause more damage more regularly.
The other reason why Yo-Yo Attacks are important is because of the interest hackers have shown in using Yo-Yo Attacks to damage websites and services. Compared to DDoS attacks, Yo-Yo attacks do not cost much to launch and do not require much expertise to execute. Generally speaking, though there are variations, DDoS attacks are volumetric attacks in the sense that DDoS attacks flood the target network with high volumes of traffic. Some DDoS attacks increase the volume of extra traffic suddenly while others increase traffic levels over time. In Yo-Yo attacks though, hackers only send extra junk traffic in bursts.