One of my account is being locked out from a windows server, it was tracked down using the Security Audit which produced event ID 4740. Its a Windows server 2012 R2 running only WSUS service. I think the account is locked almost every 90 minutes close to GPupdate run. I don't see any scheduled tasks running with that username.
I tried using Alockout.dll on the windows server 2012 R2 but it doesn't produce any logs. I think it only works for Windows server 2008. I've checked event logs on the 2012 R2 server and there isn't any logs close to the lockout time.
I checked the system for cached credentials using "rundll32 keymgr.dll,KRShowKeyMgr" but there isn't any.
Is there any application that I can use to troubleshoot and find out which service or application is causing the lockout?
Found some more details about the issue from event ID 4625 on Active directory server.
An account failed to log on.
Security ID: NULL SID
Account Name: -
Account Domain: -
Logon ID: 0x0
Logon Type: 3
Account For Which Logon Failed:
Security ID: NULL SID
Account Name: myusername
Account Domain: GFT
Failure Reason: Unknown user name or bad password.
Sub Status: 0xC000006A
Caller Process ID: 0x0
Caller Process Name: -
Workstation Name: WSUS_Server
Source Network Address: -
Source Port: -
Detailed Authentication Information:
Logon Process: NtLmSsp
Authentication Package: NTLM
Transited Services: -
Package Name (NTLM only): -
Key Length: 0
This event is generated when a logon request fails. It is generated on the computer where access was attempted.
The Subject fields indicate the account on the local system which requested the logon. This is most commonly a service such as the Server service, or a local process such as Winlogon.exe or Services.exe.
The Logon Type field indicates the kind of logon that was requested. The most common types are 2 (interactive) and 3 (network).
The Process Information fields indicate which account and process on the system requested the logon.
The Network Information fields indicate where a remote logon request originated. Workstation name is not always available and may be left blank in some cases.
The authentication information fields provide detailed information about this specific logon request.
- Transited services indicate which intermediate services have participated in this logon request.
- Package name indicates which sub-protocol was used among the NTLM protocols.
- Key length indicates the length of the generated session key. This will be 0 if no session key was requested.