How to Use LogonSessions to Detect Unauthorized Access

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LogonSessions is a free, command-line utility from Microsoft’s Sysinternals suite that lists all active user sessions on a Windows system. It is a vital tool for system administrators and cybersecurity professionals who need to audit user activity and detect unauthorized access. What is LogonSessions?

Windows creates a unique logon session every time a user, service, or system process authenticates. The LogonSessions tool queries the operating system to display these active sessions, showing details that the standard Windows Task Manager hides. It helps defenders track how accounts are interacting with a machine in real time. Key Data Provided

When you run LogonSessions, it extracts critical metadata for each active session:

Logon Session ID: A unique cryptographic identifier for the specific session.

User Name: The specific account holder or system service tied to the session.

Auth Package: The protocol used for authentication (e.g., NTLM, Kerberos, or Negotiate).

Logon Type: How the user logged in (e.g., Interactive for local logins, Network for shared folders, or Service for background tasks).

Session Time: The exact date and time the logon session was initialized. Why Security Teams Use It

LogonSessions is primarily used for security auditing, forensic analysis, and troubleshooting:

Detecting Lateral Movement: Attackers often use compromised credentials to move across a network. Security teams use this tool to spot unexpected network logon types.

Finding Rogue Processes: It reveals hidden background sessions run by services or tasks that should not be active.

Verifying Authentication Protocols: It ensures that legacy, insecure protocols like NTLM are not being used when secure alternatives like Kerberos are required. How to Use the Tool

LogonSessions runs via the Windows Command Prompt or PowerShell with administrative privileges.

Basic Enumeration: Running logonsessions prints a standard list of all current sessions to the console.

Process Mapping: Running logonsessions -p maps each logon session to the exact process IDs (PIDs) running inside it, making it easy to see what software a specific user session is executing. To help me tailor this information,

Provide a PowerShell script to automate the detection of unauthorized sessions?

Compare LogonSessions to other Sysinternals tools like PsLoggedOn? AI responses may include mistakes. Learn more

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