bXOR Operator Usage In PowerShell Command Line - PowerShell Classic

title: bXOR Operator Usage In PowerShell Command Line - PowerShell Classic
id: 812837bb-b17f-45e9-8bd0-0ec35d2e3bd6
status: test
description: |
    Detects powershell execution with that make use of to the bxor (Bitwise XOR).
    Attackers might use as an alternative obfuscation method to Base64 encoded commands.
    Investigate the CommandLine and process tree to determine if the activity is malicious.
references:
    - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=46
    - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_arithmetic_operators?view=powershell-5.1
author: Teymur Kheirkhabarov, Harish Segar
date: 2020-06-29
modified: 2024-12-11
tags:
    - attack.execution
    - attack.t1059.001
    - detection.threat-hunting
logsource:
    product: windows
    category: ps_classic_start
detection:
    selection:
        Data|contains|all:
            - 'HostName=ConsoleHost'
            - ' -bxor '
    condition: selection
falsepositives:
    - Unknown
level: low