A SIEM tool is the software that acts as an analytics-driven cybersecurity hub. All event data is recorded in one central location. The SIEM tool does the analysis and categorization for you, and more importantly, provides context that gives security analysts deeper insights into security events within the infrastructure.
SIEM technologies vary in scope. This ranges from simple log management and altering functionality to robust dashboards, machine learning and the ability to perform comprehensive analyzes with historical data.