How to remediate – Windows OS Partial Product Key (WMI)

1. Introduction

The Windows OS Partial Product Key (WMI) vulnerability allows retrieval of a partial product key from a Windows operating system. This information could assist attackers in further compromise attempts, such as bypassing activation checks or creating more convincing social engineering attacks. Systems running any supported version of Microsoft Windows are usually affected. Likely impact is low confidentiality, integrity and availability.

2. Technical Explanation

This vulnerability occurs because the Windows Management Instrumentation (WMI) interface allows access to partial product key information with appropriate credentials. An attacker who can connect remotely to a Windows host with valid user credentials can query WMI to obtain this data. This plugin does not report anything directly, but collects the information for use by other plugins.

• Root cause: The WMI interface exposes OS installation details without sufficient restriction.
• Exploit mechanism: An attacker connects to a remote Windows host using valid credentials and executes a WMI query to retrieve the partial product key.
• Scope: All versions of Microsoft Windows are potentially affected.

3. Detection and Assessment

Confirming vulnerability requires checking access to WMI information on Windows hosts. A quick check involves verifying remote connectivity, while a thorough method uses specific WMI queries.

• Quick checks: Verify you can connect remotely using supplied credentials via PowerShell or similar tools.
• Scanning: Nessus plugin ID 16389 may identify this issue as an example.
• Logs and evidence: Windows Event Logs do not directly record WMI queries for product key retrieval, making direct log analysis difficult.

powershell -Command "Get-WmiObject Win32_OperatingSystem | Select SerialNumber"

4. Solution / Remediation Steps

Remediating this vulnerability involves restricting access to WMI and implementing least privilege principles.

4.1 Preparation

• Dependencies: Ensure you have administrative privileges on the target Windows host. Roll back plan: Revert any group policy or local security policy changes made.
• A change window may be needed depending on your organisation’s policies, and should be approved by a system administrator.

4.2 Implementation

1. Step 1: Implement least privilege access controls for user accounts with remote access to Windows hosts.
2. Step 2: Review group policy settings related to WMI access permissions. Restrict access where possible.

4.3 Config or Code Example

Before

gpedit.msc (Default WMI access permissions allowing broad read access)

After

gpedit.msc (WMI access permissions restricted to specific users or groups with necessary privileges)

4.4 Security Practices Relevant to This Vulnerability

List only practices that directly address this vulnerability type. Use neutral wording and examples instead of fixed advice. For example: least privilege, input validation, safe defaults, secure headers, patch cadence. If a practice does not apply, do not include it.

• Practice 1: Least privilege access controls to limit the impact if an account is compromised.

4.5 Automation (Optional)

# Example PowerShell script to review WMI access permissions (requires testing in your environment)
Get-WmiObject Win32_SecurityDescriptor | Where-Object {$_.Path -like "*OperatingSystem"} | Select Path, Owner, Group, AccessMask

5. Verification / Validation

Confirming the fix involves verifying restricted WMI access and ensuring the partial product key cannot be retrieved with standard user credentials.

• Post-fix check: Attempt to retrieve the serial number using PowerShell as a non-administrative user. Expected output should be an error indicating insufficient permissions.
• Re-test: Re-run the command from section 3 (powershell -Command "Get-WmiObject Win32_OperatingSystem | Select SerialNumber") with standard user credentials; it should now fail.
• Monitoring: Monitor Windows Event Logs for failed WMI queries, which may indicate attempted unauthorized access (example query: Event ID 4625 – An account was successfully logged on).

powershell -Command "Get-WmiObject Win32_OperatingSystem | Select SerialNumber" (Expected output: Access Denied)

6. Preventive Measures and Monitoring

Suggest only measures that are relevant to the vulnerability type. Use “for example” to keep advice conditional, not prescriptive.

• Baselines: Update your security baseline or policy to include least privilege access controls for remote access accounts (for example, CIS control 5).
• Pipelines: Include checks in CI/CD pipelines to ensure new systems are configured with secure WMI permissions.
• Asset and patch process: Regularly review user account privileges and remove unnecessary access rights.

7. Risks, Side Effects, and Roll Back

• Roll back: Revert any group policy or local security policy changes made in section 4.2.

8. References and Resources

• Vendor advisory or bulletin: No specific vendor advisory exists for this partial key retrieval issue, but Microsoft documentation on WMI security is relevant.
• NVD or CVE entry: No specific CVE entry exists for this particular information disclosure.
• Product or platform documentation relevant to the fix: Microsoft SSH Key Management (example of secure access control).