Intrusion Detection System (IDS)
An Intrusion Detection System (IDS) is a security tool that monitors network traffic or system activity for signs of malicious behavior, policy violations, or known attack signatures, and generates alerts for security teams.
Intrusion Detection Systems are a critical component of network security monitoring. They analyze traffic patterns and system events to identify potential threats, providing security teams with the visibility needed to respond to attacks. IDS solutions are generally categorized as network-based (NIDS), which monitor traffic on network segments, or host-based (HIDS), which monitor activity on individual systems.
Detection methods fall into two primary categories: signature-based and anomaly-based. Signature-based detection compares observed activity against a database of known attack patterns, offering high accuracy for recognized threats but limited effectiveness against novel attacks. Anomaly-based detection establishes a baseline of normal behavior and flags deviations, which can catch zero-day attacks but may produce more false positives.
Deploying an IDS effectively requires strategic sensor placement, regular signature updates, proper tuning to reduce false positives, and integration with SIEM platforms for centralized analysis. While an IDS passively monitors and alerts, it does not actively block threats, which is where an Intrusion Prevention System fills the gap. Together, IDS and IPS form a comprehensive detection and response capability within a layered security architecture.