Security Information & Event Management

security information and event management (SIEM) software products and services combine security information management (SIM) and security event management (SEM). They provide real-time analysis of security alerts generated by applications and network hardware.

The acronyms SEM, SIM and SIEM have sometimes been used interchangeably, but generally refer to the different primary focus of products:

  • Log management: Focus on simple collection and storage of log messages and audit trails.
  • Security information management (SIM): Long-term storage as well as analysis and reporting of log data.
  • Security event manager (SEM): Real-time monitoring, correlation of events, notifications and console views.
  • Security information and event management (SIEM): Combines SIM and SEM and provides real-time analysis of security alerts generated by network hardware and applications.

In practice many products in this area will have a mix of these functions, so there will often be some overlap – and many commercial vendors also promote their own terminology. Often times commercial vendors provide different combinations of these functionalities which tend to improve SIEM overall. Log management alone doesn’t provide real-time insights on network security, SEM on its own won't provide complete data for deep threat analysis. When SEM and log management are combined, more information is available for SIEM to monitor.


  • Data aggregation: Log management aggregates data from many sources, including network, security, servers, databases, applications, providing the ability to consolidate monitored data to help avoid missing crucial events.
  • Correlation: Looks for common attributes, and links events together into meaningful bundles. This technology provides the ability to perform a variety of correlation techniques to integrate different sources, in order to turn data into useful information. Correlation is typically a function of the Security Event Management portion of a full SIEM solution
  • Alerting: The automated analysis of correlated events
  • Dashboards:Tools can take event data and turn it into informational charts to assist in seeing patterns, or identifying activity that is not forming a standard pattern.
  • Compliance: Applications can be employed to automate the gathering of compliance data, producing reports that adapt to existing security, governance and auditing processes.
  • Retention: Employing long-term storage of historical data to facilitate correlation of data over time, and to provide the retention necessary for compliance requirements. Long term log data retention is critical in forensic investigations as it is unlikely that discovery of a network breach will be at the time of the breach occurring.
  • Forensic analysis: The ability to search across logs on different nodes and time periods based on specific criteria. This mitigates having to aggregate log information in your head or having to search through thousands and thousands of logs.