Alert correlation is the process of linking security alerts that appear separate but are actually part of the same activity. A single login failure, a suspicious process, and unusual network traffic may look minor on their own; together they can reveal scanning, malware execution, or lateral movement. Correlation is essential because modern security tools generate large volumes of alerts, and defenders must separate real threats from routine noise.
In practice, correlation engines use shared indicators such as source IP, user account, host, time window, asset type, and attack pattern. Security teams apply it in SIEM, EDR, and OT monitoring platforms to reduce false positives and prioritize investigations. Good correlation helps analysts see the attack sequence, while poor correlation can hide a campaign or create too much confidence in low-value alerts. In industrial environments, correlation is especially useful when responses must be careful and based on context, not just raw alert volume.