What is Intruder Detection?

Intruder detection systems (IDS) monitor network traffic and/or system activity for malicious activity or policy violations. When suspicious activity is detected, the system typically logs the event and may also attempt to block or prevent the activity. IDSs can be host-based (HIDS) or network-based (NIDS), and employ various detection techniques such as signature-based detection, anomaly-based detection, and policy-based detection. They are commonly used to enhance security by identifying and responding to unauthorized access and malicious behavior that may bypass other security measures.