SecuraCorp, a leading financial institution, is worried about zero-day vulnerabilities. With a sprawling network infrastructure and multiple transaction points, it needs a system that does not…

A Network-based IDS (NIDS) monitors network traffic but doesn't specifically define how it detects threats (signature vs. anomaly), so it's less precise for the given requirement.

An anomaly-based Intrusion Detection System (IDS) establishes a baseline of normal network behavior and then identifies deviations from this baseline as potential threats. This approach is highly effective for detecting unknown (zero-day) attacks and suspicious patterns that do not match existing signatures, directly addressing the company's need.

A signature-based IDS relies on known attack patterns or signatures, making it ineffective against zero-day vulnerabilities or novel behavioral attacks, which goes against the explicit requirement.

A Host-based IDS (HIDS) monitors individual hosts, but SecuraCorp's need spans a "sprawling network infrastructure" and "suspicious patterns based on the behavior in the network," making a network-level detection method more appropriate for initial primary deployment.