Yesterday, i installed about 12 Microsoft Updates, but didnt restart server. When i opened event viewer i was shocked to see 20k+ event messages with following content An account failed to log on. Subject: Security ID: SYSTEM Account Name: (My Server Name)$ Account Domain: My_Domain_Name Logon ID: 0x3e7 Logon Type: 8 Account For Which Logon Failed: Security ID: NULL SID Account Name: aben (this names are different, like Administrator, abby, NULL SID - very different names i dont have that kind of accounts in my system) Account Domain: Failure Information: Failure Reason: Unknown user name or bad password. Status: 0xc000006d Sub Status: 0xc0000064 Process Information: Caller Process ID: 0x694 Caller Process Name: C:\Windows\System32\svchost.exe Network Information: Workstation Name: My_Server_Name Source Network Address: - Source Port: - Detailed Authentication Information: Logon Process: Advapi Authentication Package: MICROSOFT_AUTHENTICATION_PACKAGE_V1_0 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. When i rebooted my server, flood stopped.. Today, i was upgrading my Antivirus - same story, installed new version, haven't rebooted yet - Flood Returned... and again, disappeared after reboot. Any idea what this is? Virus/malware/hacked activity, or just MS code errors?

Hi, download Avira Antivir Rescue System http://www.avira.com/en/support-download-avira-antivir-rescue-system and use it on that server to perform a full scan. HTHEdoardo Benussi - Microsoft MVP Management Infrastructure - Systems Administration https://mvp.support.microsoft.com/Profile/Benussi Windows Server Italian Forum Moderator edo[at]mvps[dot]org

Hmm, so you insist it is malware?

Hmm, so you insist it is malware? As we know - in 2008 R2 everything is under auditing.. and maybe if there is content waiting to be installed after restart described above issue start to show? Why both times, it happened when system had restart pending and disappeared after..

imho, the first step to perform is a check antimalware.Edoardo Benussi - Microsoft MVP Management Infrastructure - Systems Administration https://mvp.support.microsoft.com/Profile/Benussi Windows Server Italian Forum Moderator edo[at]mvps[dot]org

My server is clear, i checked it with avira and symantec.. But, it is internet gateway for 100+ pcs...via ICS Maybe one of them is infected and trying to brute force server? Would it show svchost.exe in that case? If it is possible, how can i check which of PCs are attack source? no ip in Event, as you can see.. Any other solutions? Thanks in advance.

you have reported that logon type is 8. Logon type 8 is: This logon type indicates a network logon like logon type 3 but where the password was sent over the network in the clear text. Windows server doesn’t allow connection to shared file or printers with clear text authentication. The only situation I’m aware of are logons from within an ASP script using the ADVAPI or when a user logs on to IIS using IIS’s basic authentication mode. In both cases the logon process in the event’s description will list advapi. Basic authentication is only dangerous if it isn’t wrapped inside an SSL session (i.e. https). As far as logons generated by an ASP, script remember that embedding passwords in source code is a bad practice for maintenance purposes as well as the risk that someone malicious will view the source code and thereby gain the password. ref. http://www.windowsecurity.com/articles/Logon-Types.html try to investigate in this direction. HTHEdoardo Benussi - Microsoft MVP Management Infrastructure - Systems Administration https://mvp.support.microsoft.com/Profile/Benussi Windows Server Italian Forum Moderator edo[at]mvps[dot]org

Hello, The symptoms sound very much like a brute force attack to try and gain access to the server. They are using random account names and passwords, trying to get a match. I would recommend to change all of the administrator account passwords to something very complex. Next, you should create at least one other administrator level account, then rename and/or disable the built-in administrator account. You might want to enable netlogon logging on the server: 109626 Enabling debug logging for the Net Logon service http://support.microsoft.com/default.aspx?scid=kb;EN-US;109626 Then, start a network trace to see where the network traffic is originating from. When you notice the flood is in progress, capture network traffic for a bit, to see what's coming across, and where it's coming from. This should also show us the passwords they are sending, which will likely further convince us this is a malicious attack. Sumesh P - Microsoft Online Community Support