Creating a keytab for an AD user

Markus Moeller huaraz at moeller.plus.com
Mon Sep 24 19:42:42 EDT 2018


Hi Greg,

   I have used msktutil for some time but only for computer accounts. And 
looking again at the package I noticed the comment about the salt.

the salt of machine accounts.
  realm_name+"host"+samAccountName_nodollar+"."+lower_realm_name
(Note: samaccountname_nodollar is lower case for machine accounts)
(Note: only for DES/AES; arcfour-hmac-md5 doesn't use salts at all)

Salt for service accounts is created in a different way:
- if userPrincpalName is not set:
  realm_name+samAccountName
  (Note: samAccountName is case sensitive for service accounts)
- if userPrincpalName is set:
  realm_name + first component from userPrincpalName


I think when I last tried it was with arcfour i.e. no salt. Now with aes I 
run into the issue of a set userprincpal to the email address.


Thank you
Markus

-----Original Message----- 
From: Greg Hudson
Sent: Sunday, September 23, 2018 6:13 PM
To: Markus Moeller ; krbdev at mit.edu
Subject: Re: Creating a keytab for an AD user

On 09/23/2018 11:05 AM, Markus Moeller wrote:
>    Is that a known change (i.e. which AD attribute is used instead of the 
> user id)  and can ktutil addent get an option to set the salt ?

I do not know if Active Directory changed.  On the MIT krb5 side, we
added a -salt option to ktutil addent in release 1.16.  We also have an
unfinished feature to fetch the salt from the KDC; I can't say if and
when that work will be completed.

There is also a popular third-party tool called msktutil which may be
easier to use for this operation.

In the future, please use kerberos at mit.edu for operational questions
like this, not the development list.




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