I’m tweaking auditing and alerting again.

I like… okay no I LOVE it when I get an alert when someone fails to log into the server. Why?  Because I want to know who’s banging on my ports.  But at the same time I don’t want to be so overloaded with alerts that I can’t stand it.

So I use my Calyptix Firewall to limit my SMTP email to those IP addresses that are from Exchange Defender.  Then I limit RDP to either only be accessed via VPN or limit it to my external Static IP. 

How can you do this you ask?  Easy with SBS 2008.  Not so easy with SBS 2003.  With 2k3 you need an external firewall that can handle this.

With SBS 2008 you can do this by adjusting the inbound RDP to only be allowed from the internal IP addresses of the network AND the internal IP addresses from your remote session.

 

Now we go and adjust the default domain controllers policy to track our failures and not just our successes.

 

Add failure to those audit events so that you get those alerts.

Then right mouse click on the audit event log and kick up the size.  The default is 16384 KB which is fine for some of the other logs but small on the audit ones.

I also kick up the default auditing policy to log FAILURES.  I don’t want to see just the successes, I want to see the attempts to get in before they are successful.

And while I had stuck in Philip Elder’s alert from the www.codeplex.com/sbs

  <?xml version=”1.0″ encoding=”utf-8″ ?>
<AlertDefinitions>
<AlertDefinition ID=”e86545a3-417d-4a0a-ae42-2e6a352ebe90 Default=”1 Title=”Failed User Logon Source=”Server>
<Parameters>
  <Path>Security</Path>
  <Provider>Microsoft-Windows-Security-Auditing</Provider>
  <SetEventID>4625</SetEventID>
  </Parameters>
  </AlertDefinition>
  </AlertDefinitions>
I had forgotten to kick the group policy/auditing to alert me to failures as the default is just success.  This is the same as SBS 2003 and it something easy to kick up and IMHO very useful for security.  So I go into group policy management and kick up the default domain controller policy

 The resulting alert looks like this:

An alert was detected on your network. Further investigation into the issue is recommended.

Computer: SERVER
Date/Time generated: 11/30/2009 11:05:12 PM
Title: Failed User Logon
Source: Server
Description: 
An account failed to log on.

Subject:
 Security ID:  S-1-5-20
 Account Name:  SERVER$
 Account Domain:  DOMAIN
 Logon ID:  0x3e4

Logon Type:   3

Account For Which Logon Failed:
 Security ID:  S-1-0-0
 Account Name:  Someone
 Account Domain:  

Failure Information:
 Failure Reason:  Unknown user name or bad password.
 Status:   0xc000006d
 Sub Status:  0xc000006a

Process Information:
 Caller Process ID: 0x4c0
 Caller Process Name: C:\Windows\System32\inetsrv\w3wp.exe

Network Information:
 Workstation Name: SERVER
 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.
 

One Response to Tweaking auditing and alerting again

  1. Jake says:

    Ok, Can anyone tell me why the Source Network Addess Does not show the IP address or Port?

    (I know you can see the computer name but im more insterested in the IP address.)