Disabling Windows Defender Security Settings via PowerShelledit

Identifies use of the Set-MpPreference PowerShell command to disable or weaken certain Windows Defender settings.

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: 2 (version history)

Added (Elastic Stack release): 7.14.0

Last modified (Elastic Stack release): 7.16.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positivesedit

Planned Windows Defender configuration changes.

Rule queryedit

process where event.type == "start" and (process.name :
("powershell.exe", "pwsh.exe", "powershell_ise.exe") or
process.pe.original_file_name in ("powershell.exe", "pwsh.dll",
"powershell_ise.exe")) and process.args : "Set-MpPreference" and
process.args : ("-Disable*", "Disabled", "NeverSend", "-Exclusion*")

Threat mappingedit

Framework: MITRE ATT&CKTM

Rule version historyedit

Version 2 (7.16.0 release)
  • Updated query, changed from:

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