Intrusion Detection System
A security technology that monitors network traffic or system activities for malicious behavior, policy violations, or suspicious patterns, and generates alerts when potential threats are detected.
An Intrusion Detection System (IDS) serves as a critical monitoring layer in an organization's security infrastructure. IDS solutions come in two primary forms: network-based IDS (NIDS), which analyzes network traffic flowing through strategic points, and host-based IDS (HIDS), which monitors activities on individual systems including file integrity, log events, and process behavior. Detection methods include signature-based detection (matching known attack patterns), anomaly-based detection (identifying deviations from established baselines), and increasingly, machine learning approaches that can identify novel attack techniques.
Compliance frameworks universally expect organizations to have monitoring capabilities that detect security incidents. ISO 27001 Annex A control A.8.16 specifically addresses monitoring activities, including detection of anomalous behavior and potential security incidents. SOC 2's Common Criteria related to monitoring (CC7.2) requires organizations to monitor system components for anomalies indicative of security events. NIS2 mandates that essential and important entities implement measures for incident handling and security monitoring, which IDS directly supports. In technology due diligence, the presence and maturity of intrusion detection capabilities is a key indicator of security posture.
Modern IDS implementations are typically integrated into broader security monitoring ecosystems. Many organizations deploy IDS alongside or as part of a Security Information and Event Management (SIEM) platform, which correlates alerts from multiple sources for more accurate threat detection. Intrusion Prevention Systems (IPS) extend IDS capabilities by automatically blocking detected threats rather than just alerting. Cloud environments offer managed IDS services integrated into their platforms. Regardless of the specific implementation, organizations need to ensure they have processes for tuning detection rules, triaging alerts, investigating true positives, and continuously improving detection coverage based on the evolving threat landscape.
Related frameworks
Related terms
Endpoint Protection
Security solutions and practices designed to protect end-user devices such as laptops, desktops, mobile phones, and servers from cyber threats including malware, ransomware, and unauthorized access.
Incident Response
The organized approach to detecting, containing, investigating, and recovering from security incidents. An incident response plan defines roles, procedures, and communication protocols to minimize the impact of security breaches and other adverse events.
Network Segmentation
The practice of dividing a computer network into smaller, isolated segments or subnets to limit lateral movement, contain security breaches, and enforce granular access policies between network zones.
Security Information and Event Management
A technology platform that aggregates, correlates, and analyzes security log data from across an organization's infrastructure to detect threats, support incident investigation, and meet compliance requirements for centralized security monitoring.
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