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name: cyber-detection-engineering guardrail: true description: Designs and reviews detections from telemetry prerequisites, correlation logic, Sigma metadata, severity, status, and benign cases. Use for detection rules, Sigma review, analytic coverage, or tuning; not generic logging advice or live deployment. metadata: triggers: files: [] keywords: - detection engineering - detection rule - Sigma rule - analytic coverage - telemetry prerequisite - false positive tuning

Cyber Detection Engineering

Priority: P0 (CRITICAL)

Do not claim analytic coverage without required telemetry and executable support.

Structure

Input: analytic question, behavior hypothesis, data source/fields, retention, clock quality, scope. Process: define predicates, entity keys, window, cardinality, ordered correlation, suppression, benign cases. Output: rule/spec, prerequisites, severity, lifecycle status, fixtures, limitations, evidence record.

Rules

• A missing source, field, retention, clock, or collection path makes coverage blocked or not-tested.
• Multi-step behavior requires ordered sequence correlation over related entities/events; never substitute Boolean OR across unrelated single events.
• Sigma level expresses impact/priority (informational, low, medium, high, critical). Sigma status expresses lifecycle (stable, test, experimental, deprecated). A valid portable rule does not prove backend execution or telemetry.
• Record expected matches, exclusions and benign/false-positive cases with rationale.
• Include scope reference; skill/version/source; observation time; status; evidence references; limitations; owner. Reuse shared skill IDs.
• Production queries or modifications require documented authorization and runtime-proven controls; offline fixtures only.

Anti-Patterns

• Never write severity: high as Sigma metadata; use level: high.
• Never equate level with status, rule validity with execution, or synthetic matches with efficacy.
• Never hide missing telemetry by lowering priority or widening OR logic.

References (lazy, primary)

• Sigma specification: https://sigmahq.io/sigma-specification/specification/sigma-rules-specification.html
• MITRE ATT&CK detection strategies: https://attack.mitre.org/detectionstrategies/
• Reuse cyber-authorization, cyber-evidence, cyber-framework-mapping.