While Viewing the windows server 2008 event log, I always find many security events 4625/logon as follows:
**An account failed to log on.**
Subject:
Security ID: SYSTEM
Account Name: Sever-Name
Account Domain: WORKGROUP
Logon ID: 0x3e7
Logon Type: 10
Account For Which Logon Failed:
Security ID: NULL SID
Account Name: admin (or administrator or user or any)
Account Domain: Sever-Name
Failure Information:
Failure Reason: Unknown user name or bad password.
Status: 0xc000006d
Sub Status: 0xc000006a
Process Information:
Caller Process ID: 0x1b18
Caller Process Name: C:\Windows\System32\winlogon.exe
Network Information:
Workstation Name: Sever-Name
Source Network Address: Some-Remote-IP
Source Port: Port#No (many ports in a row)
Detailed Authentication Information:
Logon Process: User32
Authentication Package: Negotiate
The above tries comes from single IP using all possible usernames and ports.
My Questions are:
- Are these regular attacks?
- How worried should I be? Should I monitor and block every single IP or only when there are huge attack?
- Is blocking IP through windows firewall by choosing to block "All Programs" means that this IP will not be able to even use the web and email service?
- If the answer to #3 is yes, is there a way to only block the Machine / RDP Access? Is it enough?