I recently noticed on one of my servers the security log is flooded with 4624 and 4634 events, for type 3 logons under my domain admin account. The server in question is a low volume terminal server, it might average just a half dozen users connecting to it over the course of a 24 hour period. Below is a sample of one of the event log entries. I don't see much in here that helps me figure out where this is coming from, but hopefully someone else will. 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: domain\domainadmin Account Name: domainadmin Account Domain: domain Logon ID: 0xa5d57bc Logon GUID: {999a1d9d-fb64-3719-9aab-5902dad45486} 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. At this point, my security log goes back less than 2 weeks on this server because of these events. In some cases there are 10 or more events in a second. In the last 24 hours, I show 6157 events in the security log. How can I find out what is causing these? Hopefully if I can find the source, I can stop or at least throttle it...

Hi, "ss77zz"'s experience in the thread below might be helpful to you: Excessive 4624 and 4634 events http://social.technet.microsoft.com/Forums/en-US/winserverDS/thread/be9ed31f-fe8b-4b1c-a763-592243fe4c9e/ If the problem is caused by a specific terminal server, we can remove it from the domain and rejoin it as a test. Niko

Hi, "ss77zz"'s experience in the thread below might be helpful to you: Excessive 4624 and 4634 events http://social.technet.microsoft.com/Forums/en-US/winserverDS/thread/be9ed31f-fe8b-4b1c-a763-592243fe4c9e/ If the problem is caused by a specific terminal server, we can remove it from the domain and rejoin it as a test. Niko

The number of these I'm seeing are definitely not normal. While there are some normal events for users logging on and off of the terminal server, I'm seeing thousands of events a day that show MY admin account being authenticated to that server as a network logon. I wouldn't say the problem is "caused" by a specific terminal server, but rather that's where it's occurring. I suspect that the events are accurate, and I've got something running that is connecting to that server over and over again. I just have no idea what it would be or where it's coming from. Since the event doesn't list a remote computer or ip, I don't have much to go on. The only thing I can think of to try next would be to run network monitor and see if I can tell where the traffic associated with these requests might be coming from.