Web browser extensions and add-ons can be both useful and practical, but they also carry significant security risks.
Malicious browser extensions have been responsible for compromising numerous systems, with cybercriminals exploiting them to steal sensitive data, including credentials and credit card information.
In an organizational context, the stakes are even higher; these risks can lead to widespread network breaches, data leaks, and ransomware attacks.
Unfortunately, system administrators and security teams often underestimate the threats associated with web browser extensions. To mitigate these risks, organizations should restrict extension usage, permitting only those that are well-established and secure while blocking all others.
In Windows environments, this level of control can be implemented using Group Policy. In this tutorial, I will guide you through the process of creating a whitelist for approved Google Chrome extensions while blocking all others.
Pre-requisites
Before implementing the solution, assess your organization’s needs for web browser extensions. Contact various departments and compile a list of the extensions they are currently using or those they have requested.
Then, evaluate the security risk of those extensions and only accept the safe one, edited by trustworthy editors.
Once you get the list, you are ready to implement the solution.
Download the Google Chrome Policy Templates
- Download Chrome policy from this link.
- Unzip the archive and copy the content to your domain controller or your administration workstation.
Create The Group Policy
- Open the Group Policy Management console and create a new group policy “Restrict Chrome Extension“
- Edit the newly created policy and navigate to “Computer Configuration > Policies > Administrative Templates“. Right-click on the Administrative templates container and select “Add/Remove Template…” menu,
- Click on the Add button, navigate to the folder where you unzipped the Chrome policy. Under the “\policy_templates\windows\adm\en-US” select the chrome.adm file.
NB: If you use a language other than English, choose the corresponding folder.
Once you validate your selection, you will see a new folder added named “Classic Administrative Templates (ADM)“
- To prevent users from installing unauthorized Chrome extensions, navigate to “\Classic Administrative Templates (ADM)\Google\Google Chrome\Extensions“
You must configure two settings: the whitelist and the blocklist.
- Edit the “Configure extension installation allow list” setting to add the extensions that users are allowed to install.
- To add an allowed extension to the whitelist, enter the extension ID as a value.
NB: To find the extension ID, go to the Chrome extensions webstore, select the extension you want to allow and in the URL bar, copy the ID as shown in the screenshot:
- Repeat the operation for all the extensions you want to allow.
After listing the allowed extensions, you must block all the others. Otherwise, it will not work.
- Edit the “Configure extension installation blocklist” setting and enter an asterisk “*” as an extension ID value. This will prevent all extensions except those listed in the whitelist from running.
You are done.
Now, when a user tries to install an unauthorized extension, they will get the following error message:
Conclusion
In conclusion, while web browser extensions can enhance functionality and improve user experience, they also present significant security challenges that should not be overlooked. Malicious extensions have the potential to compromise sensitive organizational data, resulting in severe consequences, including data breaches and ransomware incidents.
To ensure the safety of your organization, it is crucial to establish strict policies regarding the use of browser extensions.
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