Active Directory Event Log Analysis Guide

Introduction to Active Directory Event Logs

Active Directory event logs provide crucial information about the activities and health of your domain. Proper analysis of these logs can help detect security threats, troubleshoot issues, and maintain compliance.

Key Event Logs for Active Directory

The following event logs are particularly important for Active Directory analysis:

Security Log
System Log
Directory Service Log
DNS Server Log
File Replication Service Log

Important Event IDs

Here are some critical Event IDs to monitor in your Active Directory environment:

Event ID	Description	Significance
4624	Successful logon	Monitor for unusual login patterns or times
4625	Failed logon attempt	Potential brute force attacks
4720	User account created	Track new account creations
4722	User account enabled	Monitor for unexpected account activations
4728	Member added to security-enabled global group	Track changes in group memberships
1102	Audit log cleared	Potential attempt to cover tracks
4738	User account changed	Monitor for unauthorized account modifications
5136	Directory service object modified	Track changes to AD objects
4776	Successful/failed account authentication	Credential validation attempts

Event Log Analysis Techniques

Regular Review: Establish a routine for reviewing event logs, focusing on critical events.
Baseline Establishment: Create a baseline of normal activity to easily identify anomalies.
Correlation: Look for patterns across different event logs to get a comprehensive view.
Filtering: Use built-in filtering tools or scripts to focus on relevant events.
Automation: Implement automated alerting for critical events or unusual patterns.

Using PowerShell for Event Log Analysis

PowerShell can be a powerful tool for analyzing event logs. Here's an example command to retrieve recent failed logon attempts:

Get-WinEvent -FilterHashtable @{LogName='Security';ID=4625} -MaxEvents 10 | Format-Table -Property TimeCreated,Id,Message -AutoSize -Wrap

Note: Adjust the MaxEvents parameter and add more filtering as needed for your specific analysis requirements.

Best Practices for Event Log Analysis

Centralize log collection from all domain controllers
Implement log retention policies in compliance with your organization's requirements
Use a Security Information and Event Management (SIEM) solution for advanced analysis and correlation
Regularly update your analysis criteria based on new threats and your changing environment
Conduct periodic training for IT staff on event log analysis techniques
Document and track patterns of suspicious activity over time

Tools for Event Log Analysis

Consider using these tools to enhance your event log analysis capabilities:

Event Log Explorer
Microsoft Log Parser
Splunk
Elastic Stack (ELK)

Advanced Analysis: Threat Hunting

Use event logs as a starting point for active threat hunting in your environment:

Look for signs of lateral movement
Identify potential privilege escalation attempts
Detect unusual process executions or service installations
Monitor for unauthorized changes to Group Policy Objects