Suspicious .NET Reflection via PowerShell

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This rule 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: 5m

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: 1

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"
  )

Framework: MITRE ATT&CKTM