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Windows Registry: Scheduled Task Index Value Removal to Hide Task (TaskCache)

Alerts on deletion of the Scheduled Tasks TaskCache Tree 'Index' value used by tools to enumerate tasks.

FreeReviewedSigma · Medium · v1
Product
windows
Category
registry_delete
Author
Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-08-26
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags registry delete events where the 'Index' value under the Scheduled Tasks TaskCache Tree key is removed. Removing this index can impair visibility by tools that enumerate scheduled tasks, helping attackers obscure persisted tasks. It relies on Windows registry deletion telemetry for TargetObject paths containing the TaskCache Tree location and the value name 'Index'.

Reporting behind it

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Windows Registry: Scheduled Task Index Value Removal to Hide Task (TaskCache)
Pivot detection · T1685 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.