I have 4 computers on my network. They all have the anonymous account locked and all other accounts are password protected. I'm running antivirus software (MS Security Essentials or Norton). Neither have identified any problems and I've even download Norton's power scanner and it found nothing. The problem is that I'm seen anonymous logons in the event viewer (like the one below) every couple of minutes. Should I be concerned? Log Name: Security Source: Microsoft-Windows-Security-Auditing Date: 3/21/2012 9:36:53 PM Event ID: 4624 Task Category: Logon Level: Information Keywords: Audit Success User: N/A Computer: Jim Description: 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: ANONYMOUS LOGON Account Name: ANONYMOUS LOGON Account Domain: NT AUTHORITY Logon ID: 0x289c2a6 Logon GUID: {00000000-0000-0000-0000-000000000000} Process Information: Process ID: 0x0 Process Name: - Network Information: Workstation Name: FATMAN Source Network Address: 192.168.0.27 Source Port: 3890 Detailed Authentication Information: Logon Process: NtLmSsp Authentication Package: NTLM Transited Services: - Package Name (NTLM only): NTLM V1 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. Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-A5BA-3E3B0328C30D}" /> <EventID>4624</EventID> <Version>0</Version> <Level>0</Level> <Task>12544</Task> <Opcode>0</Opcode> <Keywords>0x8020000000000000</Keywords> <TimeCreated SystemTime="2012-03-22T01:36:53.580611800Z" /> <EventRecordID>411505</EventRecordID> <Correlation /> <Execution ProcessID="584" ThreadID="624" /> <Channel>Security</Channel> <Computer>Jim</Computer> <Security /> </System> <EventData> <Data Name="SubjectUserSid">S-1-0-0</Data> <Data Name="SubjectUserName">-</Data> <Data Name="SubjectDomainName">-</Data> <Data Name="SubjectLogonId">0x0</Data> <Data Name="TargetUserSid">S-1-5-7</Data> <Data Name="TargetUserName">ANONYMOUS LOGON</Data> <Data Name="TargetDomainName">NT AUTHORITY</Data> <Data Name="TargetLogonId">0x289c2a6</Data> <Data Name="LogonType">3</Data> <Data Name="LogonProcessName">NtLmSsp </Data> <Data Name="AuthenticationPackageName">NTLM</Data> <Data Name="WorkstationName">FATMAN</Data> <Data Name="LogonGuid">{00000000-0000-0000-0000-000000000000}</Data> <Data Name="TransmittedServices">-</Data> <Data Name="LmPackageName">NTLM V1</Data> <Data Name="KeyLength">0</Data> <Data Name="ProcessId">0x0</Data> <Data Name="ProcessName">-</Data> <Data Name="IpAddress">192.168.0.27</Data> <Data Name="IpPort">3890</Data> </EventData> </Event>

Hi, May I know if you have scanned for your computer? If nothing is found, you can refer to the following articles. ANONYMOUS LOGON Print Jobs Appear in Print Queue from Users Who Are Logged on to the Domain http://support.microsoft.com/kb/323909 Event 4624 - Anonymous http://social.technet.microsoft.com/Forums/en-US/winserversecurity/thread/2a0e5f34-1237-4577-9aaa-4c029b87b68c Niki Han TechNet Community Support

Hi, May I know if you have scanned for your computer? If nothing is found, you can refer to the following articles. ANONYMOUS LOGON Print Jobs Appear in Print Queue from Users Who Are Logged on to the Domain http://support.microsoft.com/kb/323909 Event 4624 - Anonymous http://social.technet.microsoft.com/Forums/en-US/winserversecurity/thread/2a0e5f34-1237-4577-9aaa-4c029b87b68c Niki Han TechNet Community Support