Intrusion Detection Systems

An Intrusion Detection System (IDS) is a foundational cybersecurity tool, either a hardware device or software application, that passively monitors network traffic or system activities for malicious behavior and policy violations. It operates by analyzing data packets and system logs, comparing them against a database of known attack signatures (signature-based detection) or by identifying deviations from a baseline of normal activity (anomaly-based detection). When a potential threat is identified, the IDS generates an alert for security administrators to investigate, serving as a critical alarm system for unauthorized access or attacks without actively blocking the suspicious traffic itself.

1. Introduction to Intrusion Detection Systems
   1. Definition and Core Concepts
      1. What is an Intrusion Detection System
      2. Intrusion vs. Attack vs. Threat
      3. Security Event vs. Security Incident
   2. Historical Context and Evolution
      1. Early Development of IDS Technology
      2. Evolution from Simple Log Analysis
      3. Modern IDS Capabilities
   3. Primary Functions and Objectives
      1. Threat Detection and Identification
      2. Security Monitoring and Surveillance
      3. Incident Documentation and Evidence Collection
      4. Compliance and Regulatory Support
   4. Role in Cybersecurity Architecture
      1. Defense-in-Depth Strategy
      2. Integration with Security Controls
      3. Position in Security Operations Center
      4. Relationship to Incident Response