SKILL.md
Detecting WMI Persistence
When to Use
- When hunting for WMI event subscription persistence (MITRE ATT&CK T1546.003)
- After detecting suspicious WMI activity in endpoint telemetry
- During incident response to identify attacker persistence mechanisms
- When Sysmon alerts trigger on Event IDs 19, 20, or 21
- During purple team exercises testing WMI-based persistence
Prerequisites
- Sysmon v6.1+ deployed with WMI event logging enabled (Event IDs 19, 20, 21)
- Windows Security Event Log forwarding configured
- SIEM with Sysmon data ingested (Splunk, Elastic, Sentinel)
- PowerShell access for WMI enumeration on endpoints
- Sysinternals Autoruns for manual WMI subscription review
Workflow
- Collect Telemetry: Parse Sysmon Event IDs 19 (WmiEventFilter), 20 (WmiEventConsumer), 21 (WmiEventConsumerToFilter).
- Identify Suspicious Consumers: Flag CommandLineEventConsumer and ActiveScriptEventConsumer types executing code.
- Analyze Event Filters: Examine WQL queries in EventFilters for process start triggers or timer-based execution.
- Correlate Bindings: Match FilterToConsumerBindings linking suspicious filters to consumers.
- Check Persistence Locations: Query WMI namespaces root\subscription and root\default for active subscriptions.
- Validate Findings: Cross-reference with known-good WMI subscriptions (SCCM, AV products).
- Document and Remediate: Remove malicious subscriptions and update detection rules.
Key Concepts
| Concept | Description |
|---|---|
| Sysmon Event 19 | WmiEventFilter creation detected |
| Sysmon Event 20 |