Detectionhightest

Suspicious Spool Service Child Process

Detects suspicious print spool service (spoolsv.exe) child processes.

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Justin C., Thomas PatzkeCreated Sun Jul 11Updated Sun Dec 01dcdbc940-0bff-46b2-95f3-2d73f848e33bwindows

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:
    spoolsv:
        ParentImage|endswith: '\spoolsv.exe'
        IntegrityLevel:
            - 'System'
            - 'S-1-16-16384'
    suspicious_unrestricted:
        Image|endswith:
            - '\gpupdate.exe'
            - '\whoami.exe'
            - '\nltest.exe'
            - '\taskkill.exe'
            - '\wmic.exe'
            - '\taskmgr.exe'
            - '\sc.exe'
            - '\findstr.exe'
            - '\curl.exe'
            - '\wget.exe'
            - '\certutil.exe'
            - '\bitsadmin.exe'
            - '\accesschk.exe'
            - '\wevtutil.exe'
            - '\bcdedit.exe'
            - '\fsutil.exe'
            - '\cipher.exe'
            - '\schtasks.exe'
            - '\write.exe'
            - '\wuauclt.exe'
            - '\systeminfo.exe'
            - '\reg.exe'
            - '\query.exe'
    suspicious_net:
        Image|endswith:
            - '\net.exe'
            - '\net1.exe'
    suspicious_net_filter:
        CommandLine|contains: 'start'
    suspicious_cmd:
        Image|endswith: '\cmd.exe'
    suspicious_cmd_filter:
        CommandLine|contains:
            - '.spl'
            - 'route add'
            - 'program files'
    suspicious_netsh:
        Image|endswith: '\netsh.exe'
    suspicious_netsh_filter:
        CommandLine|contains:
            - 'add portopening'
            - 'rule name'
    suspicious_powershell:
        Image|endswith:
            - '\powershell.exe'
            - '\pwsh.exe'
    suspicious_powershell_filter:
        CommandLine|contains: '.spl'
    suspicious_rundll32_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    suspicious_rundll32_cli:
        CommandLine|endswith: 'rundll32.exe'
    condition: spoolsv and ( suspicious_unrestricted or (suspicious_net and not suspicious_net_filter) or (suspicious_cmd and not suspicious_cmd_filter) or (suspicious_netsh and not suspicious_netsh_filter) or (suspicious_powershell and not suspicious_powershell_filter) or all of suspicious_rundll32_* )