Windows Defender Exclusions Added via PowerShell

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Windows Defender Exclusions Added via PowerShell

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Identifies modifications to the Windows Defender configuration settings using PowerShell to add exclusions at the folder directory or process level.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.*
  • logs-windows.*

Severity: medium

Risk score: 47

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: 1

Added (Elastic Stack release): 7.14.0

Rule authors: Elastic

Rule license: Elastic License v2

Investigation guide

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Triage and analysis

Detections should be investigated to identify if the activity corresponds to legitimate activity used to put in exceptions for Windows Defender. As this rule detects post-exploitation process activity, investigations into this should be prioritized

Rule query

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process where event.type == "start" and (process.name :
("powershell.exe", "pwsh.exe") or process.pe.original_file_name :
("powershell.exe", "pwsh.exe")) and process.args : ("*Add-
MpPreference*-Exclusion*", "*Set-MpPreference*-Exclusion*")

Threat mapping

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Framework: MITRE ATT&CKTM