What is a SIEM system?

A SIEM (Security Information and Event Management) system aggregates, correlates, and analyzes log data from across an organization's IT infrastructure in real time, providing a unified view for security monitoring and incident response. Functions: Log collection: ingests logs from firewalls, IDS/IPS, endpoints, servers, applications, cloud services. Normalization: converts diverse log formats into a common schema. Correlation: applies rules to identify patterns indicating attacks (e.g., failed logins + lateral movement + data exfiltration = likely breach). Alerting: notifies SOC analysts of suspicious events. Dashboards and reporting: compliance reports, real-time security dashboards. Retention: long-term log storage for forensics and compliance. Popular SIEM platforms: Splunk, IBM QRadar, Microsoft Sentinel, Elastic SIEM, LogRhythm. SIEMs generate many alerts — tuning to reduce false positives and prioritize real threats is an ongoing challenge.