Topic starter
18/08/2026 2:46 pm
TL;DR: A SIEM that is merely running can still miss attacks, waste analyst time, and inflate storage costs, according to Expel’s diagnostic of data, detections, and team readiness. The real issue is often rule hygiene, ingestion discipline, and alert triage, not the platform itself.
Editorial analysis by NHI Mgmt Group, based on content published by Expel: “9 questions to ask about your SIEM (and what the answers reveal)”.
Key questions
Q: What does it mean when a SIEM is running but not actually performing?
A: It usually means the platform is collecting data and generating alerts, but the programme is not producing reliable detection outcomes.
Q: Why do stale rules and noisy alerts make SIEM programmes less effective?
A: They create false confidence and train analysts to distrust the queue.
Q: What are the signs that a SIEM detection strategy is failing?
A: A failing detection strategy usually shows up as persistent false positives, alert fatigue, redundant rules, and analysts spending more time cleaning up alerts than investigating them.
Practitioner guidance
- Audit log-source value against detection use cases Rank each ingestion source by the true positives it supports, the alert volume it creates, and whether it still maps to an active use case.
- Retire or tune dormant detection rules Review active rules for confirmed true positives in the last 90 days, then tune, replace, or remove rules that have become irrelevant or unproductive.
- Separate compliance retention from detection operations Move low-signal, high-retention compliance data out of the SIEM when it is not needed for detection.
Bottom line: A running SIEM is not proof of effective detection if the programme still suffers from stale rules, noisy alerting, and ungoverned ingestion.
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18/08/2026 3:28 pm
Detection maturity is a governance problem, not a platform procurement problem. A SIEM can ingest logs, fire rules, and still fail to improve security if teams do not govern source value, rule freshness, and triage quality together. The article’s core point is that maturity lives in operational discipline, not in license ownership. For security leaders, the right question is whether detection is being managed as an outcome.
A question worth separating out:
Q: How should security teams document SIEM operations so the programme survives turnover?
A: Document rule intent, data dependencies, escalation paths, tuning rationale, and ownership for each core detection area. The goal is continuity, so a new analyst can understand what the rule is supposed to catch and how to respond without depending on one expert.
👉 Read our full editorial: SIEM maturity gaps are usually detection gaps, not tool gaps