Tamper Windows Defender Remove-MpPreference - ScriptBlockLogging

Status: test
Severity: high
Log source: category ps_script, product windows
Author: Nasreddine Bencherchali (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects attempts to remove Windows Defender configuration using the 'MpPreference' cmdlet

Known false positives

Legitimate PowerShell scripts

MITRE ATT&CK coverage

Tactic	Techniques
Defense Impairment	`T1685` Disable or Modify Tools

Telemetry coverage

Provider	Record / event type
PowerShell	Event ID 4104: Creating Scriptblock text (MessageNumber of MessageTotal).

Rule body

title: Tamper Windows Defender Remove-MpPreference - ScriptBlockLogging
id: ae2bdd58-0681-48ac-be7f-58ab4e593458
related:
    - id: 07e3cb2c-0608-410d-be4b-1511cb1a0448
      type: similar
status: test
description: Detects attempts to remove Windows Defender configuration using the 'MpPreference' cmdlet
references:
    - https://techcommunity.microsoft.com/t5/core-infrastructure-and-security/windows-10-controlled-folder-access-event-search/ba-p/2326088
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-05
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_remove:
        ScriptBlockText|contains: 'Remove-MpPreference'
    selection_tamper:
        ScriptBlockText|contains:
            - '-ControlledFolderAccessProtectedFolders '
            - '-AttackSurfaceReductionRules_Ids '
            - '-AttackSurfaceReductionRules_Actions '
            - '-CheckForSignaturesBeforeRunningScan '
    condition: all of selection_*
falsepositives:
    - Legitimate PowerShell scripts
level: high

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_remove`

selection_remove:
    ScriptBlockText|contains: 'Remove-MpPreference'

Stage 2: `selection_tamper`

selection_tamper:
    ScriptBlockText|contains:
        - '-ControlledFolderAccessProtectedFolders '
        - '-AttackSurfaceReductionRules_Ids '
        - '-AttackSurfaceReductionRules_Actions '
        - '-CheckForSignaturesBeforeRunningScan '

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`ScriptBlockText`	match	`-AttackSurfaceReductionRules_Actions` `-AttackSurfaceReductionRules_Ids` `-CheckForSignaturesBeforeRunningScan` `-ControlledFolderAccessProtectedFolders` `Remove-MpPreference`	`field:"ScriptBlockText" kind:match`

Tamper Windows Defender Remove-MpPreference - ScriptBlockLogging

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_remove

Stage 2: selection_tamper

Indicators

Stage 0: `condition`

Stage 1: `selection_remove`

Stage 2: `selection_tamper`