Log correlation is the practice of linking related events from different systems so defenders can identify patterns that single logs do not show clearly.
Log correlation is the practice of connecting related events from different systems or times. In plain language, it helps defenders see that separate logs are part of one pattern rather than a pile of unrelated events.
Log correlation matters because attackers and incidents rarely stay inside one system. Suspicious identity activity, endpoint behavior, cloud administration, and network traffic may all belong to the same event chain. Looking at those events separately can hide the real story.
It also matters because defenders need efficiency. Correlation reduces the time spent manually stitching together context during triage and investigation.
Log correlation appears in SIEM, SOC workflows, alert engineering, and incident investigation. Teams correlate by time, identity, host, source, destination, user behavior, or other shared attributes to recognize suspicious sequences more clearly.
Security teams use correlation when they want to convert raw logging into meaningful detection and response context. It is especially important for multi-stage incidents that span identity, endpoint, and cloud systems.
A single failed login is not very interesting. But if correlated logs show repeated failed logins, a successful login from a new location, suspicious endpoint process activity, and rapid privilege changes shortly afterward, the organization gains a much clearer view of risk.
Log correlation is not the same as log collection. Collecting logs stores raw evidence. Correlation is the analytical step that links events into useful patterns.
It is also different from Threat Hunting. Correlation supports both routine detection and hunting, but hunting is a more hypothesis-driven investigative practice.