Detectionhightest

Suspicious PowerShell Download and Execute Pattern

Detects suspicious PowerShell download patterns that are often used in malicious scripts, stagers or downloaders (make sure that your backend applies the strings case-insensitive)

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Florian Roth (Nextron Systems)Created Mon Feb 28Updated Tue Mar 01e6c54d94-498c-4562-a37c-b469d8e9a275windows

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:
    selection:
        CommandLine|contains: # make sure that your backend applies the strings case-insensitive
            - 'IEX ((New-Object Net.WebClient).DownloadString'
            - 'IEX (New-Object Net.WebClient).DownloadString'
            - 'IEX((New-Object Net.WebClient).DownloadString'
            - 'IEX(New-Object Net.WebClient).DownloadString'
            - ' -command (New-Object System.Net.WebClient).DownloadFile('
            - ' -c (New-Object System.Net.WebClient).DownloadFile('
    condition: selection