SIEM fails when teams drown in low-quality alerts. Value comes from a limited set of well-tuned use cases wired to runbooks.
Suggested starter set: successful login after many failures, privileged account creation, credential-dumping tool execution, unusual outbound volume, and firewall rule changes.
Each use case should document data source, correlation logic, threshold, severity, and initial action. Ownerless rules die within a quarter.
Use ATT&CK coverage as a gap map, not a vanity target. Cover techniques relevant to your assets and threats first.
Monthly false-positive and response-time reviews raise quality. A rule that is always ignored should be rewritten or removed.
In Hoxy implementations we typically start with 20–30 operational use cases and expand coverage only after they stabilize.