title: Powershell AMSI Bypass via .NET Reflection
status: experimental
description: Detects Request to amsiInitFailed that can be used to disable AMSI Scanning
references:
    - https://twitter.com/mattifestation/status/735261176745988096
    - https://www.hybrid-analysis.com/sample/0ced17419e01663a0cd836c9c2eb925e3031ffb5b18ccf35f4dea5d586d0203e?environmentId=120
tags:
    - attack.execution
    - attack.defense_evasion
    - attack.t1086
author: Markus Neis
date: 2018/08/17
logsource:
    category: process_creation
    product: windows
detection:
    selection1:
        CommandLine:
            - '*System.Management.Automation.AmsiUtils*'
    selection2:
        CommandLine:
            - '*amsiInitFailed*'
    condition: selection1 and selection2
    falsepositives:
        - Potential Admin Activity
level: high