Writing Sigma Rules

Sigma is the common language for detection logic -- write once, convert to any SIEM. The value is portability and reviewability, but only if the rule is precise: a Sigma rule that matches everything is worse than no rule, because it consumes analyst time and trains the team to ignore alerts. The work is specificity without brittleness.

When to Use

• Translating a TTP, threat intel report, or incident finding into a portable detection rule
• Writing vendor-agnostic detection logic that converts to multiple SIEM backends
• Building or maintaining a detection-as-code pipeline centered on Sigma
• Reviewing or tuning existing Sigma rules for precision and false-positive reduction
• Converting Sigma rules between backends (Splunk, Elastic, Sentinel, CrowdStrike, Chronicle)
• Contributing rules upstream to SigmaHQ or maintaining a private rule repository

When NOT to Use