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 Interlock RAT FileFix Download-Cradle via PowerShell WebClient with PowerShell User-Agent (via ps_script)
Malicious Metasploit Stager Delivery via mshta Remote HTA (via process_creation)
Suspicious PowerShell Download of Disguised Payload to ProgramData
Suspicious PowerShell WebClient Download of Executable Payload
Malicious Script Host Spawning PowerShell in Gootloader Chain
Suspicious PsExec Service Launching Encoded PowerShell Payload
Suspicious PowerShell Remote Script Execution via IEX DownloadString
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.