With the prevalence of USB ports and removable storage devices, it's crucial to implement robust measures to safeguard sensitive information and prevent data breaches. One effective way to achieve this is by leveraging Group Policy Objects (GPO) on Windows machines to control USB port access and enforce data loss prevention (DLP) policies. In this blog post, we'll explore how to secure USB ports to disallow write access to removable storage devices and implement Data Loss Prevention (DLP) using GPO.

What are Group Policy Objects (GPO)?

Group Policy Objects (GPO) are a feature in Microsoft Windows Active Directory that allows administrators to control the working environment of user accounts and computer accounts. GPOs are powerful tools for managing security settings, configurations, and other aspects of Windows machines across an organization.

Understanding the Risks

USB ports offer convenient connectivity but also pose significant security risks. Unauthorized use of USB storage devices can lead to data theft, introduction of malware, and compliance violations. Therefore, it's essential to restrict access to these ports and prevent data exfiltration.

Step 1: Accessing Group Policy Editor

• Open Group Policy Editor: Press Windows Key + R to open the Run dialog, type gpedit.msc, and press Enter.
• Navigate to USB Policies: In the Group Policy Editor, go to Computer Configuration -> Administrative Templates -> System -> Removable Storage Access.

Step 2: Configuring USB Policies

• Disable USB Ports: To prevent USB devices from being recognized and used on Windows machines, enable the policy "All Removable Storage classes: Deny all access".
• Allow Specific Devices: If certain USB devices are essential for your organization, you can allow them while blocking others. Use the policy "All Removable Storage classes: Deny execute access" and specify the Device IDs for allowed devices.
• Restrict by Device Classes: You can restrict access based on device classes (e.g., storage devices, imaging devices, etc.) using the "Removable Disks: Deny read access" and "Removable Disks: Deny write access" policies.

Step 3: Applying GPO to Organizational Units (OU)

• Link GPO to OU: Once you've configured the desired USB policies, link the GPO to the appropriate Organizational Unit (OU) containing the target computers.