/GCR-Google-Calendar-RAT

Google Calendar RAT is a PoC of Command&Control over Google Calendar Events

Primary LanguagePythonMIT LicenseMIT

GCR
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GCR - Google Calendar RAT

Google Calendar RAT is a PoC of Command&Control (C2) over Google Calendar Events, This tool has been developed for those circumstances where it is difficult to create an entire red teaming infrastructure. To use GRC, only a Gmail account is required. The script creates a 'Covert Channel' by exploiting the event descriptions in Google Calendar. The target will connect directly to Google." It could be considered as a layer 7 application Covert Channel (but some friends would say it cannot be :) very thanks to my mates "Tortellini" https://aptw.tf )

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POC

poc

How it works

GCR attempt to connect to a valid shared Google Calendar link and after generating a unique ID check for any yet-to-be-executed commands. If it is not able to find any command, it creates a new one (fixed to "whoami") as a proof of connection. Every event is composed by two part:

  1. The Title, which contains the unique ID, it means you can schedule multiple commands creating events having the same unique ID as name

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  1. The Description, which contains the command to execute and the base64 encoded output using the pipe symbol as separator "|"

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Workflow Attack

Disegno senza titolo (2)

What a SOC analyst/Blue Teamer will see?

Focusing specifically on the network aspect, the only connections established will be to Google's servers, making the connection appear completely legitimate. Let's check with process hacker: image image

which results in this image image

How to use it

  • Setup a Google service account and obtain the credentials.json file, place the file in the same directory of the script
  • Create a new Google calendar and share it with the new created service account
  • Edit the script to point your calendar address
  • Once executed on the target machine an event with a unique target ID is automatically created autoexecuting the "whoami" command
  • Use the following syntax in the event description for the communication => CLEAR_COMMAND|BASE64_OUTPUT

    Examples:

    • "whoami|"
    • "net users|"
  • The date is fixed on May 30th, 2023. You can create unlimited events using the unique ID as the event name.

Disclaimer and notes

I prefer to consider this project as a game rather than an experiment :) Please do not use it for illegal purpose. I take no responsibility for the use that will be made of it

IT IS JUST A POC IN PYTHON, PLEASE DO NOT ASK ME HOW TO WEAPONIZE IT!

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