Telemetry is the security data collected from endpoints, networks, identity systems, and cloud services. It includes logs, alerts, process events, network flows, authentication records, file activity, and other signals that help defenders reconstruct what happened on a system or inside a tenant.
In cyber security, telemetry matters because attackers often try to hide their tracks while moving, staging files, or exfiltrating data. Good telemetry lets analysts spot suspicious logins, unusual outbound transfers, disabled defenses, or abnormal cloud access patterns and then connect those events into a timeline. In incident response, telemetry is often the difference between a rumor and evidence: a leak-site claim may suggest compromise, but endpoint and cloud telemetry can confirm whether data was actually accessed, copied, or removed. Rich, well-retained telemetry also improves detection engineering, hunting, and post-incident forensics.