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PowerShell ScriptBlock Obfuscation via MSHTA VBScript CreateObject Execution

Alerts on PowerShell script blocks containing mshta and VBScript createobject/.run/window.close patterns consistent with obfuscated execution.

FreeReviewedSigma · High · v2
Product
windows
Category
ps_script
Author
Nikita Nazarov, oscd.community (SigmaHQ), DRL 1.1
Published
2020-10-08
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Execution → Defense Evasion

  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 identifies PowerShell script block content that includes multiple MSHTA and VBScript execution indicators in the same block, suggesting obfuscated or staged execution. Attackers often use MSHTA with VBScript to launch processes while hiding intent within scripted content. The detection relies on Script Block Logging telemetry by matching specific string combinations within ScriptBlockText.

Reporting behind it

Related detections9 linkedT1027 — drag to rearrange
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Suspicious XOR Obfuscated PowerShell from ClickFix Distribution
Suspicious PowerShell Executing Code from Environment Variable (via process_creation)
Suspicious In-Memory Runspace Execution via PowerShell Script Block
Suspicious Encoded PowerShell Using Base64 Stream Decompression Routines (via process_creation)
Suspicious PowerShell In-Memory Execution with AES Decryption
Suspicious Encoded PowerShell Command Execution
Suspicious PEAKLIGHT Memory-Only PowerShell Downloader Flags (via process_creation)
Obfuscated PowerShell Script: Indirect Cmdlet Execution via ExportedCommands Array Index
PowerShell ScriptBlock Obfuscation via MSHTA VBScript CreateObject Execution
Pivot detection · T1027 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. v1
    No changelog recorded for this version.2026-07-30

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