PowerShell PSAsyncShell Reverse Shell Activity via Script Block Logging

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
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

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PowerShell PSAsyncShell Reverse Shell Activity via Script Block Logging

Pivot detection · T1059.001 · 9 related

Changelog

v2

v2
Candidate ingested via manual entry.2026-07-31
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.

windows-powershell-psasyncshell-asynchronous-tcp-reverse-shell-afd3df04

title: PowerShell PSAsyncShell Reverse Shell Activity via Script Block Logging
id: 5b93f9af-80a7-421f-b9b6-f6af87f710b2
status: test
description: 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.
references:
  - https://github.com/JoelGMSec/PSAsyncShell
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_script/posh_ps_psasyncshell.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-10-04
tags:
  - attack.execution
  - attack.t1059.001
logsource:
  product: windows
  category: ps_script
  definition: "Requirements: Script Block Logging must be enabled"
detection:
  selection:
    ScriptBlockText|contains: PSAsyncShell
  condition: selection
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: afd3df04-948d-46f6-ae44-25966c44b97f
    type: derived

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