Uncommon PowerShell HostApplication Values in Windows PowerShell Start Logs

Detects PowerShell classic start events with unusual HostApplication values that may indicate evasion of powershell.exe-focused detections.

FreeReviewedSigma · Medium · v5

Product: windows
Category: ps_classic_start
Author: Roberto Rodriguez @Cyb3rWard0g (SigmaHQ), DRL 1.1
Published: 2019-08-11
Updated: 2026-07-31

Analysis Detection

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 startup events where the recorded HostApplication value does not match common PowerShell interpreter paths or simple 'powershell' invocations. Attackers may use alternate host application strings to evade detections that only look for the standard powershell.exe invocation. The detection relies on Windows PowerShell classic start telemetry containing a Data field with 'HostApplication=' entries.

Reporting behind it

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Uncommon PowerShell HostApplication Values in Windows PowerShell Start Logs

Pivot detection · T1059.001 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
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-uncommon-hostapplication-values-in-ps-classic-start-telemetry-d7326048

title: Uncommon PowerShell HostApplication Values in Windows PowerShell Start Logs
id: 9343952f-0fe0-41ef-9758-a2eeab07aee8
related:
  - id: 64e8e417-c19a-475a-8d19-98ea705394cc
    type: derived
  - id: d7326048-328b-4d5e-98af-86e84b17c765
    type: derived
status: test
description: This rule flags PowerShell startup events where the recorded HostApplication value does not match common PowerShell interpreter paths or simple 'powershell' invocations. Attackers may use alternate host application strings to evade detections that only look for the standard powershell.exe invocation. The detection relies on Windows PowerShell classic start telemetry containing a Data field with 'HostApplication=' entries.
references:
  - https://threathunterplaybook.com/hunts/windows/190815-RemoteServiceInstallation/notebook.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules-threat-hunting/windows/powershell/powershell_classic/posh_pc_alternate_powershell_hosts.yml
author: Roberto Rodriguez @Cyb3rWard0g, Huntrule Team
date: 2019-08-11
modified: 2025-10-22
tags:
  - attack.execution
  - attack.t1059.001
  - detection.threat-hunting
logsource:
  product: windows
  category: ps_classic_start
detection:
  selection:
    Data|contains: HostApplication=
  filter_main_ps:
    Data|contains:
      - HostApplication=?:/Windows/System32/WindowsPowerShell/v1.0/powershell
      - HostApplication=?:/Windows/SysWOW64/WindowsPowerShell/v1.0/powershell
      - HostApplication=?:\Windows\System32\sdiagnhost.exe
      - HostApplication=?:\Windows\System32\WindowsPowerShell\v1.0\powershell
      - HostApplication=?:\Windows\SysWOW64\sdiagnhost.exe
      - HostApplication=?:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell
      - HostApplication=powershell
  filter_optional_citrix:
    Data|contains: Citrix\ConfigSync\ConfigSync.ps1
  filter_optional_hexnode:
    Data|contains: HostApplication=C:\Hexnode\Hexnode Agent\Current\HexnodeAgent.exe
  condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
  - Programs using PowerShell directly without invocation of a dedicated interpreter
  - MSP Detection Searcher
  - Citrix ConfigSync.ps1
level: medium
license: DRL-1.1

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