huntrule

Suspicious Cleo Autorun Health Check File Drop (via file_event)

PremiumReviewedSigma · High · v1
Product
windows
Category
file_event
Author
HuntRule
Published
2026-09-06
Updated
2026-09-06
AnalysisDetection

ATT&CK techniques

Initial Access → Execution

  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 detects creation of healthcheck.txt or healthchecktemplate.txt files inside a Cleo autorun directory. Operators exploited the Cleo autorun feature by writing these files to trigger execution of an embedded PowerShell stager.

Reporting behind it

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Malicious IIS w3wp Worker Spawning Command Interpreter via SharePoint Web Shell
Suspicious SolarWinds Web Help Desk Java Process Spawning Command Shell
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Suspicious Cleo Autorun Health Check File Drop (via file_event)
Pivot detection · T1059.001 · 9 related

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