huntrule

Suspicious In-Memory Runspace Execution via PowerShell Script Block

PremiumReviewedSigma · Medium · v1
Product
windows
Category
ps_script
Author
HuntRule
Published
2026-10-24
Updated
2026-10-24
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 detects PowerShell script content that creates a new runspace and passes deobfuscated code to Invoke-Expression. A profile resident backdoor uses a dedicated runspace and script block to run its command and control loop in memory without touching disk.

Reporting behind it

Related detections9 linkedT1027 — drag to rearrange
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Suspicious PowerShell In-Memory Execution with AES Decryption
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Suspicious PEAKLIGHT Memory-Only PowerShell Downloader Flags (via process_creation)
Obfuscated PowerShell Script: Indirect Cmdlet Execution via ExportedCommands Array Index
Suspicious PowerShell String Concatenation Obfuscation for Batch Extension via LNK (via process_creation)
Suspicious PowerShell Spawned from PyInstaller MEI Extraction Folder (via process_creation)
Suspicious PowerShell Encoded Command Execution
Suspicious PowerShell Invoke-Expression with Replace Obfuscation
Suspicious In-Memory Runspace Execution via PowerShell Script Block
Pivot detection · T1027 · 9 related

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