  Security issues related to the cloud computing are relevant to various
stakeholders for an informed cloud adoption decision. Apart from data breaches,
the cyber security research community is revisiting the attack space for
cloud-specific solutions as these issues affect budget, resource management,
and service quality. Distributed Denial of Service (DDoS) attack is one such
serious attack in the cloud space. In this paper, we present developments
related to DDoS attack mitigation solutions in the cloud. In particular, we
present a comprehensive survey with a detailed insight into the
characterization, prevention, detection, and mitigation mechanisms of these
attacks. Additionally, we present a comprehensive solution taxonomy to classify
DDoS attack solutions. We also provide a comprehensive discussion on important
metrics to evaluate various solutions. This survey concludes that there is a
strong requirement of solutions, which are designed keeping utility computing
models in mind. Accurate auto-scaling decisions, multi-layer mitigation, and
defense using profound resources in the cloud, are some of the key requirements
of the desired solutions. In the end, we provide a definite guideline on
effective solution building and detailed solution requirements to help the
cyber security research community in designing defense mechanisms. To the best
of our knowledge, this work is a novel attempt to identify the need of DDoS
mitigation solutions involving multi-level information flow and effective
resource management during the attack.
