Windows Server 2016 - KDC has no support for encryption type while getting initial credentials

[Todd Grayson]

oops, typo by me:

You are hard forcing AES for initial ticket granting ticket with the
settings you are using for enctypes.

Should read

You are hard forcing AES for initial session key and ticket granting ticket
with the settings you are using for enctypes.

On Thu, Nov 8, 2018 at 9:35 AM Todd Grayson <tgrayson at cloudera.com> wrote:

> You are hard forcing AES for initial ticket granting ticket with the
> settings you are using for enctypes.   Unset (comment out) the 3 enctype
> lines for one of your tests.  How to comment out lines in the krb5.conf is
> covered in the second paragraph here:
>
>
> https://web.mit.edu/kerberos/krb5-latest/doc/admin/conf_files/krb5_conf.html
>
> Use klist -ef after you successfully authenticate and inspect the ticket
> encryption types used.  It will look something like this after commenting
> out those lines I mentioned and then retrying your kinit:
>
> dude at host:~$ kinit Administrator at AD.SEC.EXAMPLE.COM
> Password for Administrator at AD.SEC.EXAMPLE.COM:
> dude at host:~$ klist -ef
> Ticket cache: FILE:/tmp/krb5cc_1000
> Default principal: Administrator at AD.SEC.EXAMPLE.COM
>
> Valid starting       Expires              Service principal
> 11/08/2018 09:16:00  11/08/2018 19:16:00  krbtgt/
> AD.SEC.EXAMPLE.COM at AD.SEC.EXAMPLE.COM
> renew until 11/15/2018 09:15:53, Flags: FRIA
> Etype (skey, tkt): arcfour-hmac, aes256-cts-hmac-sha1-96
>
> You can see on the Etype line, by default the inital session key is
> actualy rc4-hmac  (arcfour-hmac is same thing, just different names) But
> the actual ticket granting ticket. The above example is against a windows
> 2008 KDC, but 2016 is probably doing the same thing for backward
> comparability.
>
>
> Kerberos will negotiate strongest encryption types by default within the
> available configuration.
>
> AD exposes per user account settings in the properties dialog, under
> account details, that allow you to set using AES encryption types.  Doing
> it for all accounts would be a global policy in AD.  This mail list does
> not really cover how to manage active directory as a KDC at that level,
> microsoft discussion boards would be best there.
>
> Given you are new to kerberos, I would suggest starting here, reading this
> will help you understand your terminology, what to search/google for, how
> things work in kerberos, etc.
>
> http://www.kerberos.org/software/tutorial.html
>
> The administration guide would be next step.
>
> Microsoft AD kerberos info is here, I would start with this AFTER going
> through the kerberos tutorial.
>
>
> https://docs.microsoft.com/en-us/windows/desktop/secauthn/microsoft-kerberos
>
>
>
> On Thu, Nov 8, 2018 at 9:03 AM Silambarasan Madhappan <
> silambarasan19 at gmail.com> wrote:
>
>> Hi,
>>
>> I am new to Kerberos.  I am not able to obtain Kerberos
>> ticket-granting tickets with strong encryption types from "Windows
>> Server 2016 AD"
>>
>> My client kerberos configuration as below
>> ========================
>>
>> $ cat /etc/krb5.conf
>> [libdefaults]
>> default_realm = CIFS.COM
>> default_tkt_enctypes = AES256-CTS-HMAC-SHA1-96 AES128-CTS-HMAC-SHA1-96
>> default_tgs_enctypes = AES256-CTS-HMAC-SHA1-96 AES128-CTS-HMAC-SHA1-96
>> preferred_enctypes = AES256-CTS-HMAC-SHA1-96 AES128-CTS-HMAC-SHA1-96
>> ccache_type = 2
>>
>> [realms]
>> CIFS.COM = {
>> kdc = WIN.cifs.com:88
>> }
>>
>> [domain_realm]
>> .cifs.com = CIFS.COM
>>
>> [logging]
>> kdc = FILE:/var/log/krb5kdc.log
>> admin_server = FILE:/var/log/kadmin.log
>> default = FILE:/var/log/krb5lib.log
>> [bash4.2]$
>>
>> Issue :
>> =====
>> $ kinit Administrator
>> kinit(v5): KDC has no support for encryption type while getting
>> initial credentials
>> $
>>
>> Please let me know  where can I find the kdc configuration types in
>> Active Directory (Windows Server 2016) ?
>> Do I have to change any configuration on Kerberos Client or Server ?
>> Please help me on this.
>>
>> Thanks,
>> Silambarasan M
>> ________________________________________________
>> Kerberos mailing list           Kerberos at mit.edu
>> https://mailman.mit.edu/mailman/listinfo/kerberos
>>
>
>
> --
> Todd Grayson
> Customer Operations Engineering
> Security SME
>
>

-- 
Todd Grayson
Customer Operations Engineering
Security SME