title: Powershell Defender Exclusion
id: 17769c90-230e-488b-a463-e05c08e9d48f
status: experimental
description: Detects requests to exclude files, folders or processes from Antivirus scanning using PowerShell cmdlets
references:
    - https://docs.microsoft.com/en-us/microsoft-365/security/defender-endpoint/configure-process-opened-file-exclusions-microsoft-defender-antivirus
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1562.001/T1562.001.md
tags:
    - attack.defense_evasion
    - attack.t1562.001
author: Florian Roth
date: 2021/04/29
modified: 2021/07/12
logsource:
    category: process_creation
    product: windows
detection:
    selection1:
        CommandLine|contains: 'Add-MpPreference '
    selection2:
        CommandLine|contains:
            - ' -ExclusionPath '
            - ' -ExclusionExtension '
            - ' -ExclusionProcess '
    selection_encoded:
        CommandLine|contains:
            - 'QWRkLU1wUHJlZmVyZW5jZ'
            - 'FkZC1NcFByZWZlcmVuY2'
            - 'BZGQtTXBQcmVmZXJlbmNl'
    condition: ( selection1 and selection2 ) or selection_encoded
falsepositives:
    - Possible Admin Activity
    - Other Cmdlets that may use the same parameters
level: high