huntrule

PowerShell PSAsyncShell Reverse Shell Activity via Script Block Logging

Detects PowerShell use of PSAsyncShell by matching the tool name in logged script block text.

FreeReviewedSigma · High · v2
Product
windows
Category
ps_script
Author
Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-10-04
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

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 flags PowerShell script block content that contains the string "PSAsyncShell", indicating use of a TCP reverse shell tool. Reverse shells enable attackers to establish outbound interactive access and maintain persistence or remote control. The detection relies on PowerShell Script Block Logging telemetry that records executed script block text.

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange
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Malicious Mass Hyper-V Virtual Machine Shutdown via PowerShell by Kraken Ransomware
Suspicious PowerShell WebClient DownloadFile of Archive Payload (UAT-7237)
Suspicious SharePoint Worker Process Spawning Command Interpreter via ToolShell
Malicious Emmenhtal JavaScript Loader Spawning Encoded PowerShell
Suspicious Python Interpreter Launching Encoded PowerShell via subprocess
PowerShell PSAsyncShell Reverse Shell Activity via Script Block Logging
Pivot detection · T1059.001 · 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.