How to Detect and Analyze Privilege Escalation Using Windows Event Logs

Privilege escalation attacks involve gaining elevated access to a system or account, often as a precursor to further malicious activity. Detecting such events requires monitoring specific logs for privilege changes, process behavior, and unauthorized activity.

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1. Monitor for Account Privilege Changes

What to Look For:

• Special Privileges Assigned:

  • Event ID 4672: Captures the assignment of special privileges during logon, such as SeDebugPrivilege or SeTakeOwnershipPrivilege.

• Group Membership Changes:

  • Event ID 4732: Detects when a user is added to a security-enabled local group, such as Administrators.

Red Flags: Accounts being granted elevated privileges or added to critical groups without a valid reason.

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2. Investigate Service Installations

What to Look For:

• Unauthorized Service Installations:

  • Event ID 4697: Logs the installation of new services, which attackers may use to maintain persistence with elevated access.

Red Flags: Services with unusual names or descriptions, especially those installed outside standard administrative activity.

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3. Check for Process Creation with Elevated Privileges

What to Look For:

• Process Creation Logs:

  • Event ID 4688: Tracks processes launched with elevated privileges, identified by a "High" integrity level.

• Correlate with User Activity:

  • Compare the process creation with the account and user logon events to determine if the activity aligns with typical usage.

Red Flags: Processes like cmd.exe, powershell.exe, or taskmgr.exe launched with elevated privileges by non-administrative users.

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4. Review Scheduled Tasks

What to Look For:

• Task Creation and Modification:

  • Event ID 4698: Logs the creation of scheduled tasks.

  • Event ID 4702: Logs modifications to existing tasks.

• Suspicious Task Details:

  • Tasks created to execute scripts, binaries, or other tools at elevated privilege levels.

Red Flags: Tasks scheduled by non-administrative accounts or designed to run outside regular maintenance windows.

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5. Detect Bypass of User Account Control (UAC)

What to Look For:

• Unusual Use of Binaries:

  • Logs showing the use of tools commonly associated with UAC bypass, such as:

    • msiexec.exe

    • schtasks.exe

    • rundll32.exe

• Behavioral Patterns:

  • Repeated attempts to bypass UAC mechanisms or execute binaries with elevated privileges.

Red Flags: UAC bypass techniques triggered outside of legitimate administrative workflows.

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6. Correlate with Access Logs

What to Do:

• Analyze Privileged Access:

  • Compare privilege escalation events with access logs to detect suspicious activity, such as:

    • Access to sensitive directories or files.

    • Changes to system configurations.

• Follow the Trail:

  • Link privileged actions to subsequent events, such as data exfiltration attempts or lateral movement.

Red Flags: Privileged accounts accessing resources unrelated to their role or outside normal operating hours.

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7. Immediate Action

What to Do:

• Disable the Compromised Account: Immediately revoke access for any account found to have unauthorized privilege escalation.

• Investigate the Source: Determine how the attacker gained elevated privileges, focusing on:

  • Vulnerable applications.

  • Exploited configurations.

  • Credential compromise.

• Remove Elevated Privileges: Revert any unauthorized privilege changes or group memberships.

• Validate System Integrity: Ensure critical systems and files remain unchanged and free from tampering.

Post-Incident Steps:

• Audit Privileges: Conduct a thorough review of user and system privileges to identify unnecessary access.

• Enhance Monitoring: Implement detection rules in your SIEM to flag privilege escalation attempts proactively.

• Educate Administrators: Train IT staff to recognize signs of privilege escalation and respond effectively.

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Conclusion

By systematically analyzing Windows Event Logs, such as those for account privilege changes, service installations, and process creations, you can detect and respond to privilege escalation attempts early. Combining log analysis with network and behavioral monitoring ensures a robust defense against attackers seeking elevated access.