NTFS & Shared folder security permission best practice for the AD SYSVOL directory

Question

I have located in most of my client's AD Domain controllers, the SYSVOL directory \\domain.com\SYSVOL\domain.com\

This subdirectory contains all files ranging from PowerShell and Batch scripts, .MSI files, Fonts, Microsoft Office Templates and also image files for Group Policy and software deployments.

I noticed that the files and folders within that directory have been granted full control to Authenticated Users. This can be quite risky as it leaves them vulnerable to potential modification by attackers or ransomware.

Please suggest to me what to configure instead without impacting the Group Policy to deploy the Desktop Wallpapers and other Software deployments.

Answer 1

Hi,

Basically User should only have read and execute permissions, also backup the DCs just in case there is a modification of the permissions and something goes wrong you will have it backed up.

Check the process toreset the permissions using ICALs - https://www.stigviewer.com/stig/windows_server_2016/2018-09-05/finding/V-73371#:~:text=By%20default%2C%20this%20will%20be,permissions%2C%20this%20is%20a%20finding.

Hope this helps.

JS

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Answer 2

Hello EnterpriseArchitect,

Thank you for your question and for reaching out with your question today.

You are correct in identifying the potential security risks associated with granting full control to the Authenticated Users group on the SYSVOL directory. Leaving sensitive files and scripts open to modification by any authenticated user can lead to security breaches or unauthorized changes to critical configurations.

To improve security while still allowing necessary functionality for Group Policy deployments, consider implementing the following best practices:

1. Use Group Policy Object (GPO) Security Filtering: Instead of granting full control to the Authenticated Users group on the entire SYSVOL directory, use Group Policy security filtering to apply specific GPOs only to the necessary security groups or organizational units (OUs). This way, you can limit the scope of GPOs to the intended recipients while protecting sensitive configurations from unauthorized access.
2. Avoid Storing Sensitive Information: Avoid storing sensitive information such as passwords or sensitive scripts within Group Policy Preferences. If you need to deploy scripts, consider using Group Policy settings to run scripts from a secure, restricted location on the network where access is tightly controlled.
3. Enable Advanced Auditing: Enable advanced auditing on the SYSVOL directory to monitor changes to files and folders. This can help you track any unauthorized modifications and take action in case of security incidents.
4. Regular Backups: Implement a regular backup strategy for the SYSVOL directory. This ensures that you have a reliable copy of critical configurations in case of accidental modifications or security incidents.
5. Least Privilege Principle: Apply the principle of least privilege when configuring permissions on the SYSVOL directory. Only grant the minimum required permissions to the necessary groups or users.
6. Consider Group Policy Central Store: If your environment has multiple Domain Controllers, you can create a Group Policy Central Store, which is a centralized location for storing Group Policy Administrative Templates. The central store simplifies administration and ensures consistent templates across all Domain Controllers without granting unnecessary permissions.

By implementing these best practices, you can enhance the security of the SYSVOL directory while still maintaining the necessary functionality for Group Policy deployments. Regularly review and test your configurations to ensure that they align with your organization's security requirements. Additionally, consider consulting with security experts or conducting security audits to identify and address potential vulnerabilities in your environment.

I used AI provided by ChatGPT to formulate part of this response. I have verified that the information is accurate before sharing it with you.

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