Intrusion detection systems play a vital role in network security. Central to these systems is the language used to express policies. Ideally, this language should be powerful, implementation-agnostic, and cross-platform. Unfortunately, today.s popular intrusion detection systems fall short of this goal.

Each has their own policy language in which expressing complicated logic requires implementation-specific code. Database systems have adapted SQL to handle streaming data, but have yet to achieve the efficiency and flexibility required for complex intrusion detection tasks.

Chimera is a declarative query language for network traffic processing that bridges the gap between powerful intrusion detection systems and a simple, platform-independent SQL syntax.

Chimera extends streaming SQL languages to better handle network traffic by adding structured data types, first-class functions, and dynamic window boundaries. We show how these constructs can be applied to real-world scenarios, such as side-jacking detection and DNS feature extraction.