Event 4624 null sid – Repeated security log

I have several of security log entries with the event 4624 followed shortly by an event 4634. Since it seams the entries for anonymous logon, I had started to analyze whether it has legitimate reason or it is filling up as unwanted . After I have googled, I found following things 

– Event 4624 null sid is the valid event but not the actual user’s logon event.
– The reason for the no network information is it is just local system activity.  Windows talking to itself.
– The “anonymous” logon has been part of Windows domains for a long time–in short, it is the permission that allows other computers to find yours in the Network Neighborhood

Event ID 4624 null sid

An account was successfully logged on.

Subject:
 Security ID:  NULL SID
 Account Name:  -
 Account Domain:  -
 Logon ID:  0x0

Logon Type:   3

New Logon:
 Security ID:  SYSTEM
 Account Name:  MyPC$
 Account Domain:  MyDomain
 Logon ID:  0x42c5ffa3
 Logon GUID:  {a17cec34-483b-2d22-04e7-5bc572fe8ebc}

Process Information:
 Process ID:  0x0
 Process Name:  -

Network Information:
 Workstation Name: 
 Source Network Address: -
 Source Port:  -

Detailed Authentication Information:
 Logon Process:  Kerberos
 Authentication Package: Kerberos
 Transited Services: -
 Package Name (NTLM only): -
 Key Length:  0

This event is generated when a logon session is created. It is generated on the computer that was accessed.

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 occurred. The most common types are 2 (interactive) and 3 (network).

The New Logon fields indicate the account for whom the new logon was created, i.e. the account that was logged on.

The network 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.
 - Logon GUID is a unique identifier that can be used to correlate this event with a KDC event.
 - 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.

Get rid of event 4624 null sid

     The event 4624 is controlled by the audit policy setting Audit logon events.  In 2008 r2 and later versions and Windows 7 and later versions, this Audit logon events setting is extended into subcategory level.

Category: Audit logon events (Logon/Logoff)
Subcategory: Logon – ( In 2008 r2 or Windows 7 and later versions only)
Subcategory: Logoff – ( In 2008 r2 or Windows 7 and later versions only)

If these audit settings enabled as Success we will get the following event ids

4624: An account was successfully logged on
4634: An account was logged off
4647: User initiated logoff in the case of Interactive and RemoteInteractive (remote desktop) logons

If these audit settings enabled as failure we will get the following event id
4625: An account failed to log on

Possible solution: 1 -using Auditpol.exe

     If you would like to get rid of this event 4624 then you need to run the following commands in an elevated command prompt (Run As Administrator):

Auditpol /set /subcategory:"Logon" /Success:disable

Then update gpo by this command

gpupdate /force

Note: Use this command to disable both logon and logoff activity

Auditpol /set /category:"Logon/Logoff" /Success:disable

Possible solution: 2 -using Local Security Policy

     You can stop 4624 event by disabling the setting Audit Logon in Advanced Audit Policy Configuration of Local Security Policy.

    1. Press the key Windows + R
    2. Type command secpol.msc, click OK
    3. Then go to the node Advanced Audit Policy Configuration->Logon/Logoff.

    4. Check the audit setting Audit Logon If it is configured as Success, you can  revert it Not Configured and Apply the setting.

Possible solution: 2 -using Group Policy Object

If the setting is inherited from any other GPO to Local Security Policy,You need to edit the specific GPO which is configured with the setting Audit Logon/Logoff. You can find target GPO by running Resultant Set of Policy.
 
   1. Press the key Windows + R 
 
   2. Type command rsop.msc, click OK.

   3. Now you can the below result window. Then go to the node Computer Configuration ->Windows Settings ->Local Polices-> Audit Policy.

Note : This article is applies to Windows Server 2008,Windows Server 2008 R2, Windows Server 2012, Windows 7 and Windows 8.

Thanks,
Morgan
Software developer