Detectionmediumtest

User Added to Local Administrators Group

Detects addition of users to the local administrator group via "Net" or "Add-LocalGroupMember".

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Launch
Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)Created Fri Aug 12Updated Thu Mar 02ad720b90-25ad-43ff-9b5e-5c841facc8e5windows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic
Detection Logic2 selectors
detection:
    selection_main:
        - CommandLine|contains|all:
              # net.exe
              - 'localgroup '
              - ' /add'
        - CommandLine|contains|all:
              # powershell.exe
              - 'Add-LocalGroupMember '
              - ' -Group '
    selection_group:
        CommandLine|contains:
            - ' administrators '
            - ' administrateur' # Typo without an 'S' so we catch both
    condition: all of selection_*
False Positives

Administrative activity