Security Information and Event Management (SIEM) is software that combines security information management (SIM) and security event management (SEM). It collects logs from network devices, applications, servers and other sources to detect threats, ensure compliance with regulations, and aid investigations. Key features of SIEM include log collection, user activity monitoring, real-time event correlation, log retention, compliance reports, file integrity monitoring, log forensics, and customizable dashboards. SIEM solutions can be deployed in various ways including self-hosted, cloud-based, or as a hybrid model managed by the organization or a managed security service provider.