A Web Application Firewall (WAF) includes anti-distributed denial of service (DDoS) capabilities designed to protect cloud-hosted applications and underlying data storage from availability-based attacks. Managing Cloud principles state that WAFs sit in front of web applications and analyze incoming traffic to identify and block malicious requests, including high-volume attack patterns characteristic of DDoS attacks.

By filtering traffic at the application layer, a WAF prevents excessive or malicious requests from overwhelming backend services such as cloud storage systems and databases. Many WAF solutions implement rate limiting, traffic profiling, and behavioral analysis to distinguish legitimate users from attackers, ensuring continued access to cloud resources.

The other options do not provide DDoS protection. An XML gateway focuses on validating and securing XML-based messages. NDAM and ADAM solutions monitor database activity but do not mitigate network-level or application-layer flood attacks. Therefore, the Web Application Firewall is the correct security device for providing anti-DDoS protection in cloud environments.