Telemetry
What is Telemetry?
The logs and signals an organisation collects from its own systems, which is the only source that answers whether something reached you.
Telemetry is the logs, events and signals an organisation collects from its own systems: endpoint events, authentication logs, DNS queries, proxy records, firewall flows and cloud audit trails.
External threat intelligence says what is happening in the world. Only your own telemetry can say whether it happened to you. The quality of every investigation depends on what telemetry exists, how long it is kept and whether anyone can search it.