Active Directory Locked Account Investigation Process

This article outlines the process to identify and resolve account lockout in an Active Directory environment.

Process

Process1.png

1) Change lockout policy according to Microsoft Recommendation

 

The lockout policy’s ultimate goal is to protect against automated password guessing (brute-force attack) and as such, the value should be high enough so that accounts are not accidentally locked out by an end user or incorrect saved password.

 

 

 

As per the following articles, I would recommend the following lockout settings

 

  • Account lockout threshold 50
  • Reset account lockout counter after 10 minutes

 

https://technet.microsoft.com/en-us/library/cc671957(v=ws.10).aspx

https://technet.microsoft.com/en-us/library/hh994574(v=ws.11).aspx

 

Lockout-Policy.png

2) Enabling Auditing

 

Identifying the source of the account lockouts in a complex environment will be virtually impossible without auditing enabled.

 

Please note: Only events that occurred after enabling auditing will be logged. It also might be necessary to increase Security log file size

 

Audit-Policy.png

 

3) Identify source device that lockout occurred on

 

3.1) Event Comb

 

 

Part of Account Lockout and Management Tools https://www.microsoft.com/en-us/download/details.aspx?id=18465

 

Still a useful tool in a pinch.

Please note: Built-in search for account lockout is not using the newer event IDs. To search newer IDs, add 4625 4740 4771 4768 4776 to the list

 

For details on these events, see

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=529

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=4625

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=644

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=4740

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=675

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=4771

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=676

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=4768

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=681

https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=4776

 

EventCombMT-1.png
EventCombMT-2.png

 

All gathered events from selected domain controllers will be saved into text files in the temp folder
event.png

3.2) Lockout Status

 

 

Part of Account Lockout and Management Tools https://www.microsoft.com/en-us/download/details.aspx?id=18465

 

When you start tool you specify the user account to inspect.

 

Please note: If the lock device is a Domain Controller, you have to follow the trail until you get to the actual source device name

 

LockoutStatus.png

3.3) AD Audit

 

 

See https://www.manageengine.com/products/active-directory-audit

 

My personal favorite, AD Audit makes finding the source account that locks device super easy, just use built-in reports

 

ADAudit.jpg

 

4.1) Powershell

 

Get-LockedOutLocation

https://gallery.technet.microsoft.com/scriptcenter/Get-LockedOutLocation-b2fd0cab

 

lock1.png

4) Identify source process that locked account

 

4.1) NetWrix Account Lockout Examiner

 

 

See https://www.netwrix.com/account_lockout_examiner.html

 

Install NetWrix Account Lockout Examiner on another computer. After that run it and point to the device that generates lockouts.

 

Lockout.JPG

4.2) ADAudit

 

 

See https://www.manageengine.com/products/active-directory-audit

 

As I said before, my personal favorite. After finding source account that locks device using built-in reports, the Account Lockout Analyzer can show the source process that locks accounts

 

ADAudit3.jpg

 

5) Implement processes to prevent future lockouts

 

5.1 Windows Services, Scheduled Tasks and COM Objects

Utilize service accounts with strong non-expiring passwords or managed service accounts.

5.2 Drive Mappings

Do not map drives with explicit username and password. Utilize Group Policy User Drive Map Preference to map the drive mappings.

Drive-Map-1.png

Drive-Map-2.png5.3 Logon Sessions

Implement RDP inactive/idling session logoff.

 

 

5.4 Credential Manager

 

Disable Credential Manager service. This will prevent users from saving/using stored passwords

 

Credential-Manager.jpgTips

If your account that you are using for the investigation is locking, rename your username for the duration of the investigation

 

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