Suspicious .NET Reflection via PowerShell

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Detects the use of Reflection.Assembly to load PEs and DLLs in memory in PowerShell scripts. Attackers use this method to load executables and DLLs without writing to the disk, bypassing security solutions.

Rule type: query

Rule indices:

  • winlogbeat-*
  • logs-windows.*

Severity: high

Risk score: 73

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Defense Evasion

Version: 2 (version history)

Added (Elastic Stack release): 8.0.0

Last modified (Elastic Stack release): 8.1.0

Rule authors: Elastic

Rule license: Elastic License v2

Rule query

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event.category:process and powershell.file.script_block_text : (
"[System.Reflection.Assembly]::Load" or
"[Reflection.Assembly]::Load" )

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 2 (8.1.0 release)
  • Formatting only