Check Primary Authentication Protocol for Active Directory (NTLM or Kerberos?)

Question

How can I check, from a client machine (in Global Group)(also is local admin), whether the domain controller is authenticating my login request to the domain using NTLM or Kerberos?

I know that Kerberos is enabled by default, but the domain Admin can always force clients to auth with other Protocols. So i just want to be sure which protocal they are using. Are there any methods to do to check?

Any help would be appreciated

Please see http://serverfault.com/questions/31850/how-do-you-find-out-if-active-directory-is-using-kerberos-or-ntlm — Ryan Ries, Apr 11 '15 at 15:51

Ryan Ries · Accepted Answer · 2015-04-11T18:38:54.890

Greg's answer is alright, but your question specifically states that you want to check this from the client, not from the domain controller. So I'll take a crack at it.

First way, enable Kerberos logging on your client:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\Kerberos\Parameters
    LogLevel DWORD 0x1

Once Kerberos logging is enabled, then, log into stuff and watch the event log. If you're using Kerberos, then you'll see the activity in the event log. If you are passing your credentials and you don't see any Kerberos activity in the event log, then you're using NTLM.

Second way, you can use the klist.exe utility to see your current Kerberos tickets. This will definitely help you if you are authenticating to a service for the first time, because you will be getting a new ticket... but for subsequent authentications to the same service, you can reuse the same ticket, and so klist.exe may be of limited use to you.

Third way, watch the authentication happen with Wireshark.

score 5 · Answer 2 · edited Aug 17 '20 at 16:10

One way would be to check the domain controller Security event log for Event ID 4624 (logon) events, where the AuthenticationPackageName is NTLM or Kerberos. You should also verify that your Domain Controllers have auditing enabled, and are capturing the required auditing events.

You can create custom Event Viewer filters to make this easier, and filter on other fields like the username or workstation name:

<QueryList>  
  <Query Id="0" Path="Security">
    <Select Path="Security">*[EventData[Data[@Name="AuthenticationPackageName"] = "NTLM"] and System[(EventID=4624)]]</Select>
  </Query> 
</QueryList>  


<QueryList>  
  <Query Id="0" Path="Security">
    <Select Path="Security">*[EventData[Data[@Name="AuthenticationPackageName"] = "Kerberos"] and System[(EventID=4624)]]</Select>
  </Query> 
</QueryList>

NTLM

Kerberos

score -1 · Answer 3 · answered Apr 11 '15 at 15:24

-1

You can force your client to only use one or the other to ensure that you're using Kerberos (or NTLM if you prefer that for some reason).

Microsoft has a guide which you may find helpful. It tells how to assess and restrict NTLM usage. Auditing and restricting NTLM usage guide

answered Apr 11 '15 at 15:24

GuitarPicker

394
1
8

Sorry sir but it appears that you didn't answer his question. – Ryan Ries Apr 11 '15 at 15:26
My answer was that by disabling NTLM the OP could determine whether or not the admin had Kerberos blocked or vice versa. Do I need to also explain how to disable NTLM for this to be considered an answer? – GuitarPicker Apr 11 '15 at 15:28
2

OP never mentioned disabling anything, and disabling NTLM completely isn't even feasible in most scenarios. – Ryan Ries Apr 11 '15 at 15:29
It's technically correct that if you force authentication to only one protocol, by definition you will know what protocol is in use. That is not a very useful answer, of course. – mfinni Apr 11 '15 at 16:09
I understand that disabling NTLM completely may break some programs, but it is still a valid way to temporarily test to see if the domain admin is forcing authentication using some other protocol which is what the OP is trying to determine. If the OP disables NTLM and suddenly can't authenticate, then the admin is most likely forcing NTLM. Likewise if disabling Kerberos instead breaks login, then the admin may be forcing Kerberos. If neither breaks login, then the admin accepts both, and it may be trickier to determine which one is preferred. – GuitarPicker Apr 11 '15 at 16:42

Check Primary Authentication Protocol for Active Directory (NTLM or Kerberos?)

3 Answers3