Mitigation Strategies and Implementation: Limiting Token Privileges Using Local Security Policy

When dealing with Windows SYSTEM account exploitation, one effective mitigation technique is limiting token privileges using Local Security Policy (secpol.msc). This strategy helps reduce the attack surface by restricting what SYSTEM-level tokens can do, preventing privilege escalation and lateral movement.

Step-by-Step Implementation:

1. Open Local Security Policy

• Press Win + R, type secpol.msc, and hit Enter.
• Navigate to Local Policies > User Rights Assignment.

2. Restrict High-Risk Privileges

• Identify sensitive privileges such as:
• Double-click each privilege and remove unnecessary user accounts and groups, limiting them to system-critical processes.

3. Implement Token Filtering

• Modify Local Security Policy to enforce strict Least Privilege Access principles.
• Restrict SYSTEM processes to only the required privileges.

4. Apply Group Policy for Enterprise-Wide Enforcement

• Open Group Policy Editor (gpedit.msc).
• Navigate to:

Computer Configuration > Windows Settings > Security Settings > Local Policies > User Rights Assignment        

• Modify the same privilege settings as in secpol.msc, but at a domain-wide level.

5. Audit and Monitor SYSTEM Privilege Usage

• Use Windows Event Viewer (eventvwr.msc): Go to Security Logs and filter by Event ID: 4673 (A privileged service was called) 4674 (An operation was attempted on a privileged object) Look for abnormal SYSTEM token usage.

6. Regularly Review and Update Privilege Assignments

• Periodically audit privileged accounts using:

whoami /priv        

• Ensure no unauthorized accounts hold SYSTEM privileges.

By properly configuring Local Security Policy and enforcing privilege restrictions, you can reduce the risk of SYSTEM token abuse. Implementing these mitigations makes it significantly harder for attackers to escalate privileges or perform unauthorized actions within the Windows environment.