Exploiting WhatsApp Web Session via Chrome Profile Backup

Cross-Platform Exploitation of Google Chrome Profile Vulnerability Using Backup Restoration

To exploit this vulnerability, a full backup of the Google Chrome Profile Folder is required. The process is operating system independent, meaning the backup can be utilized across platforms like macOS, Windows, or Ubuntu. By creating a new Chrome profile on any computer and replacing the newly created profile’s files with the backed-up original Chrome Profile data, the vulnerability can be exploited. This approach allows for seamless migration and exploitation of user data or settings across different machines and operating systems.

  1. Open Chrome
    Start Google Chrome on your device, either using the Default Profile or any other profile that you wish to back up.
  2. Log in to WhatsApp Web
    Navigate to web.whatsapp.com and log in by scanning the QR code with the WhatsApp mobile app. Wait for the synchronization to complete, ensuring that your messages and contacts load fully.
  3. Close Chrome
    After successful synchronization, close the Chrome browser completely.
  4. Access Chrome Profile Folder (macOS Example)
    On macOS, open the following directory:
    /Users/{username}/Library/Application Support/Google/Chrome.
    Locate the folder corresponding to the profile you used (e.g., „Default“ for the Default Profile).
  5. Copy the Chrome Profile Folder
    Copy the entire profile folder (e.g., „Default“) from this location. This backup will contain all user data, including active WhatsApp Web sessions.
    (Note: This process is OS-independent, meaning the profile can be copied from macOS and used on Windows, Linux, etc.)
  6. Transfer the Profile to Another Device
    On any other device (Windows, Linux, or another macOS machine), navigate to the respective Chrome profile directory (e.g., on Windows: C:\Users\{username}\AppData\Local\Google\Chrome\User Data) and replace the existing profile folder (e.g., „Default“) with the previously copied one from the original device.
  7. Open Chrome on the New Device
    Launch Chrome on the new device, using the profile you have just copied.
  8. Access WhatsApp Web
    Open web.whatsapp.com again. The WhatsApp Web session from the original device will still be active, without the need to log in again. All incoming messages will be viewable, and new messages can be sent directly from this new device.

Key Insight:
Access to the Chrome profile directory alone is sufficient to hijack an active WhatsApp Web session. By copying and transferring the profile, a WhatsApp Web instance can be taken over on another device, giving full access to messages and the ability to send new ones, without requiring further authentication.

Additional Note:
This behavior may also apply to other services that do not adequately verify the environment in which they are operating. Specifically, services that do not check for hardware identifiers or changes in IP or MAC addresses could be similarly vulnerable. This means that any service relying on browser profiles for session management could potentially be exploited in the same way.