Decoding Windows Token Privileges with PowerShell – A Practical Guide

Understanding the Challenge

Security professionals often encounter cryptic numerical values in logs, such as the currenttokenprivenabled field in Sentinel logs. These values often appear as a single decimal number, leaving analysts to wonder what they actually represent.

In Windows security, this number is typically a derived bitmask that indicates which privileges are enabled in a token. However, unlike traditional bitfields, Windows does not natively store privileges this way. Instead, privileges are managed as an array of LUID_AND_ATTRIBUTES structures.

This writeup explores how to decode these numerical values into meaningful privilege names using PowerShell and the LookupPrivilegeValue API. The goal is to provide a practical way to analyze token privileges for security audits, red teaming, and forensic investigations. There is also a Powershell tool on my GitHub that you can download to perform these lookups. Download Tool on Github

Example Output:

Bridging the Gap with PowerShell

The core problem lies in the representation of token privileges. While many tools attempt to simplify the process by adopting a bitmask approach, Windows internally manages privileges differently. This PowerShell script dynamically retrieves privilege identifiers (LUIDs) and maps them to their corresponding privileges, making it easier to analyze security logs.

How It Works

Dynamic Lookup

The script iterates through a predefined list of well-known Windows privileges, such as SeCreateTokenPrivilege and SeDebugPrivilege, and retrieves their LUIDs using the LookupPrivilegeValue API.

Derived Bitmask Computation

For each privilege, the script calculates a bitmask using the formula:

1 << LUID.LowPart          

For example, if LookupPrivilegeValue returns a LUID with LowPart = 1 for SeCreateTokenPrivilege, then its bitmask becomes:

1 << 1  →  0x2        

Mapping and Verification

Once the bitmask is computed, it is compared against the decimal value found in logs. If the corresponding bit is set, the privilege is marked as enabled.

The script produces a structured output that maps privilege names to their:

- LUID values

- Computed bitmask (in hexadecimal)

- Enabled status

Why This Matters

Simplified Analysis

Security logs often present data in formats that are not immediately actionable. Converting a single decimal value into a list of privileges makes it easier to audit token security and investigate potential threats.

Support for Red and Blue Teams

- Red Teams can use this script to identify privileges enabled on a compromised system, revealing potential escalation paths.

- Blue Teams can audit token privileges to detect anomalies and ensure that unexpected privileges are not enabled.

Bridging the Gap

Because Windows natively stores privileges as an array rather than a bitmask, security analysts often struggle to interpret privilege settings efficiently. This script provides an effective and structured way to analyze privileges in environments where a bitmask-based approach is used.

Official Documentation and Further Reading

While Microsoft does not officially document privilege mappings as bitmask values, the following references provide background on how privileges are structured:

- TOKEN_PRIVILEGES structure

- LUID_AND_ATTRIBUTES structure

- LookupPrivilegeValue function

Download tool on github