Detectionhightest

Suspicious Mshta.EXE Execution Patterns

Detects suspicious mshta process execution patterns

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Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)Created Sat Jul 17Updated Tue Feb 21e32f92d1-523e-49c3-9374-bdb13b46a3bawindows

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_img:
        - Image|endswith: '\mshta.exe'
        - OriginalFileName: 'MSHTA.EXE'
    selection_susp:
        # Suspicious parents
        ParentImage|endswith:
            - '\cmd.exe'
            - '\cscript.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\regsvr32.exe'
            - '\rundll32.exe'
            - '\wscript.exe'
        # Suspicious folders
        CommandLine|contains:
            - '\AppData\Local\'
            - 'C:\ProgramData\'
            - 'C:\Users\Public\'
            - 'C:\Windows\Temp\'
    filter_img:
        # Filter legit Locations
        - Image|startswith:
              - 'C:\Windows\System32\'
              - 'C:\Windows\SysWOW64\'
        # Suspicious extensions
        - CommandLine|contains:
              - '.htm'
              - '.hta'
        # Filter simple execution
        - CommandLine|endswith:
              - 'mshta.exe'
              - 'mshta'
    condition: all of selection_* or (selection_img and not filter_img)