An intrusion detection system (IDS) is a device or software application that monitors a network or systems for malicious activity or policy violations. Any malicious activity or violation is typically reported either to an administrator or collected centrally using a security information and event management (SIEM) system.
There are four main types of IDS:
- Network intrusion detection system (NIDS)
- Host-based intrusion detection system (HIDS)
- Perimeter Intrusion Detection System (PIDS)
- VM based Intrusion Detection System (VMIDS)