Robert, a cloud architect, received a huge bill from the cloud service provider, which usually...

Robert, a cloud architect, received a huge bill from the cloud service provider, which usually doesn't happen. After analyzing the bill, he found that the cloud resource consumption was very high. He then examined the cloud server and discovered that a malicious code was running on the server, which was generating huge but harmless traffic from the server. This means that the server has been compromised by an attacker with the sole intention to hurt the cloud customer financially. Which attack is described in the above scenario?