How to remediate – USB Drives Enumeration (WMI)

1. Introduction

2. Technical Explanation

This vulnerability occurs because the Windows Management Instrumentation (WMI) interface allows querying information about connected USB devices using supplied credentials. An attacker can connect to a remote host and execute WMI queries to retrieve this data. The primary requirement for exploitation is valid user credentials with sufficient permissions to access WMI on the target system. There is no specific CVE associated with this enumeration, but it represents a common reconnaissance technique.

• Root cause: Insufficient restriction of information accessible via WMI.
• Exploit mechanism: An attacker uses WMI queries (e.g., using PowerShell or WMIC) to list connected USB drives and their properties. For example, Get-WmiObject Win32_USBControllerDevice can be used to enumerate devices.
• Scope: Windows operating systems are affected. Specific versions are not known to be more vulnerable than others; the issue depends on WMI configuration.

3. Detection and Assessment

You can confirm vulnerability by checking if you can list USB drives connected to a remote host using your current credentials. A quick check involves attempting to query WMI from a remote machine.

• Quick checks: Run wmic /node:"remote_hostname" path Win32_USBControllerDevice get DeviceID, PNPDeviceID replacing “remote_hostname” with the target system’s name. If you receive a list of USB devices, the host is likely vulnerable.
• Scanning: Nessus plugin ID 10874 can identify this issue as an example. Other scanners may have similar checks.
• Logs and evidence: Review Windows Event Logs for WMI activity (Event IDs related to WMI query execution). Look for events associated with the Win32_USBControllerDevice class.

wmic /node:"remote_hostname" path Win32_USBControllerDevice get DeviceID, PNPDeviceID

4. Solution / Remediation Steps

Ensure that external USB drive usage aligns with your organization’s security policy. Restrict access to WMI where possible.

4.1 Preparation

• Dependencies: Ensure you have administrative privileges on the target system. Roll back plan: Restore from backup if issues occur.
• Change window: Consider a scheduled maintenance window for significant configuration changes. Approval may be needed by security or IT management.

4.2 Implementation

1. Step 1: Review your organization’s USB drive policy and enforce it through Group Policy or other management tools.
2. Step 2: Implement least privilege principles, limiting user access to WMI only when necessary.
3. Step 3: Consider disabling WMI if not required for business functions (this may impact other applications).

4.3 Config or Code Example

Before

// No specific WMI configuration example - assume default access

After

// Example PowerShell script to restrict WMI access (requires testing)
# Set-WmiAccessControl -Path "rootcimv2" -Identity GroupName -Rights Read,Execute
# Replace GroupName with the appropriate user or group.

4.4 Security Practices Relevant to This Vulnerability

Several security practices can mitigate this vulnerability.

• Practice 1: Least privilege reduces the impact if an attacker gains access. Limit user accounts’ permissions to only what is needed for their role.
• Practice 2: Input validation, while not directly applicable to WMI enumeration itself, helps prevent exploitation of other vulnerabilities that might be exposed through similar interfaces.

4.5 Automation (Optional)

No specific automation script is provided due to the complexity and potential impact of modifying WMI access controls.

5. Verification / Validation

• Post-fix check: Run wmic /node:"remote_hostname" path Win32_USBControllerDevice get DeviceID, PNPDeviceID. You should receive an error indicating access is denied or a failure to connect.
• Re-test: Re-run the earlier detection method (WMI query) to confirm it no longer works with your current credentials.
• Smoke test: Ensure any applications relying on WMI functionality continue to operate as expected.
• Monitoring: Monitor Windows Event Logs for failed WMI queries, which could indicate an attempted enumeration.

wmic /node:"remote_hostname" path Win32_USBControllerDevice get DeviceID, PNPDeviceID

6. Preventive Measures and Monitoring

Update security baselines to reflect the implemented WMI access restrictions. Regularly review patch cycles.

• Baselines: Update your Windows security baseline or CIS control settings to include least privilege principles for WMI access.
• Pipelines: Consider adding checks in CI/CD pipelines to ensure that WMI configurations are consistent with security policies.
• Asset and patch process: Implement a regular review cycle (e.g., monthly) to verify WMI configurations on critical systems.

7. Risks, Side Effects, and Roll Back

• Risk or side effect 1: Applications relying on WMI might stop functioning if access is restricted too severely. Mitigation: Carefully test changes in a non-production environment.
• Roll back: Restore from backup if issues occur. Revert any changes made to WMI access control lists.

8. References and Resources

Links related to this vulnerability.

• Vendor advisory or bulletin: No specific vendor advisory exists for this enumeration issue, but refer to Microsoft documentation on WMI security.
• NVD or CVE entry: No specific CVE entry exists for this enumeration issue.
• Product or platform documentation relevant to the fix: Microsoft WMI Security.