The service commonly recommended for protecting web applications from internet threats including site scripting and database manipulation attacks (such as SQL injection) is a web application firewall. This service enables rules to be configured that filter out malicious traffic based on predefined conditions.

A DDoS protection service is more aligned with defending against high-volume traffic attacks that aim to make a service unavailable, not for filtering specific attack types like SQL injection or cross-site scripting.

A threat detection service focuses on identifying suspicious activity within an environment but does not act as a barrier against application-level exploits.

An automated security assessment tool is designed for scanning and assessing potential security issues within an environment but doesn't directly intercept or filter incoming traffic to stop application-level attacks.