title: Formbook Process Creation
status: experimental
description: Detects Formbook like process executions that inject code into a set of files in the System32 folder, which executes a special command command line to delete the dropper from the AppData Temp folder. We avoid false positives by excluding all parent process with command line parameters.
author: Florian Roth
date: 2019/09/30
references:
    - https://inquest.net/blog/2018/06/22/a-look-at-formbook-stealer
    - https://app.any.run/tasks/388d5802-aa48-4826-b069-250420504758/
    - https://app.any.run/tasks/8e22486b-5edc-4cef-821c-373e945f296c/
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        # Parent command line should not contain a space value
        # This avoids false positives not caused by process injection
        # e.g. wscript.exe /B sysmon-install.vbs
        ParentCommandLine: 'C:\Windows\System32\\*.exe'
        CommandLine: 
            - '*\cmd.exe /c del "C:\Users\\*\AppData\Local\Temp\\*.exe'
            - '*\cmd.exe /c del "C:\Users\\*\Desktop\\*.exe'
    condition: selection
fields:
    - CommandLine
    - ParentCommandLine
falsepositives:
    - Unknown
level: critical