Windows Failed Logon Investigation (Event ID 4625)

Overview

This lab demonstrates how to investigate failed authentication attempts using Windows Event Viewer.

Security teams monitor Event ID 4625 to detect brute force attacks, credential guessing attempts, and unauthorized login activity.

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Scenario

Multiple failed login attempts were generated on a Windows system.

The goal of this investigation was to:

• Identify failed authentication events
• Analyze login attempt details
• Understand how security logs record authentication failures

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Tools Used

• Windows Event Viewer
• Windows Security Logs

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Investigation Steps

Step 1 — Navigate to Security Logs

Open Event Viewer and navigate to:

Windows Logs → Security

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Step 2 — Filter Event ID 4625

Filter the security log to show only failed logon attempts.

Event ID:

4625

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Step 3 — Review Failed Logon Events

The filtered results show multiple failed authentication attempts recorded by the system.

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Step 4 — Analyze Event Details

Event details reveal important authentication information such as:

• Source Network Address
• Authentication Package
• Logon Process
• Account Domain

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Key Findings

• Event ID 4625 represents a failed logon attempt

• Security logs capture detailed authentication information

• Failed login events can indicate:

  • brute force attacks
  • credential guessing attempts
  • unauthorized login activity

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Security Insight

Monitoring Event ID 4625 helps security teams detect potential attacks and investigate suspicious login behavior within an environment.