building-detection-rule-with-splunk-spl

# Building Detection Rules with Splunk SPL ## Overview Splunk Search Processing Language (SPL) is the primary query language used in Splunk Enterprise Security for building correlation searches that detect suspicious events and patterns. A well-crafted detection rule aggregates, correlates, and enriches security events to generate actionable notable events for SOC analysts. Enterprise SIEMs on average cover only 21% of MITRE ATT&CK techniques, making skilled SPL rule writing essential for closing detection gaps. ## When to Use - When deploying or configuring building detection rule with splunk spl capabilities in your environment - When establishing security controls aligned to compliance requirements - When building or improving security architecture for this domain - When conducting security assessments that require this implementation ## Prerequisites - Splunk Enterprise Security (ES) deployed and configured - Access to Splunk Search & Reporting app with appropriate roles - Understanding of Common Information Model (CIM) data models - Familiarity with MITRE ATT&CK framework techniques - Knowledge of the organization's log sources and data flows ## Core SPL Detection Rule Patterns ### 1. Threshold-Based Detection Detects events exceeding a defined count within a time window. ```spl index=wineventlog sourcetype=WinEventLog:Security EventCode=4625 | stats count as failed_logins dc(TargetUserName) as unique_users by src_ip | where failed_logins > 10 AND unique_users...