Detection Engineering

• Alert volume is untuned noise unless rules carry the discipline of code: tests, review, and revision history.
• ATT&CK mapping turns 'we alert on X' into a coverage story leadership and blue teams can reason about.
• Detections decay: environments change, adversaries adapt, so rules need a lifecycle, not a one-time write.

Fixed rules quietly rot; tuned detections evolve with the environment and the threat landscape.

• Covert techniques translate to data queries through the ATT&CK lens: technique, then the telemetry that exposes it.
• Sigma rules give a vendor-neutral detection language that ports across SIEMs.
• Rules are tested against attack simulations and peacetime traffic; false positives are tuned, not buried.
• Version the rules, review them, and report coverage: technique coverage beats raw alert count as a metric.

• A team converts its 'new user runs powershell.exe -enc' alert into a Sigma rule mapped to T1059.001 with exclusions.
• Detection backlog prioritizes techniques by threat-intel relevance and asset sensitivity, not effort spent writing rules.
• Quarterly rule review drops detections with zero hits and unreachable logic, or fixes their blind spots.

• Write the rule next to its ATT&CK technique and the exact telemetry fields it relies on.
• Test with a real simulation, then measure signal-to-noise over at least two weeks.
• Version rules in git; a detection you cannot review is a checkbox, not a control.
• Report coverage as technique-to-detection mapping, so gaps are visible decisions.

• Porting a rule into a SIEM without ever testing it against your actual data schema.
• Deleting noisy rules instead of tuning them, quietly losing coverage.
• Writing detections that depend on fields the environment does not collect.
• Confusing 'alert fires' with 'detected an intrusion' in the coverage story.

• When a rule never fires, prove your data flow: generate the log line, confirm the index, then check the rule fields.
• When a rule floods, triage 10 alerts and group their root causes before tuning exclusions.
• Pin rule review to the ATT&CK update cadence; technique revisions are when detections need revision.

• Detections reveal your environment's blind spots; store rules as sensitive as your SIEM itself.
• Adversaries read public detection content too; tune with baseline behavior on top of published patterns.
• An alerting pipeline is itself a trust boundary — protect its build and deploy path from tampering.