[cifs-protocol] How to determine if an account should use AES?

Sebastian Canevari Sebastian.Canevari at microsoft.com
Fri Aug 28 15:35:36 MDT 2009

Matthieu / Andrew,

I'm attaching a revised version of [MS-KILE]section where the KDC behavior is described for the cases in which the the msDS-SupportedEncryptionTypes is not populated.

Upcoming versions of the document will reflect the changes with same or very similar wording.

I'm still working in providing you a complete and accurate set of responses for your latest set of questions regarding this matter.

Thanks and regards,


Sebastian Canevari
Senior Support Escalation Engineer, US-CSS DSC PROTOCOL TEAM
7100 N Hwy 161, Irving, TX - 75039
"Las Colinas - LC2"
Tel: +1 469 775 7849
e-mail: sebastc at microsoft.com

-----Original Message-----
From: Matthieu Patou [mailto:mat at matws.net] 
Sent: Monday, August 24, 2009 5:22 PM
To: Andrew Bartlett
Cc: Sebastian Canevari; pfif at tridgell.net; cifs-protocol at samba.org; Interoperability Documentation Help
Subject: Re: [cifs-protocol] How to determine if an account should use AES?

Hello Sebastian,

I'm coming back to you on this subject.
Last week I made tests with one of the newsest version of samba4 which 
tries to pretend to be have a windows 2008 forest/domain and dc 
compatibility level.

And I didn't noticed any request from a windows 2008 acting as a client 
of my S4 domain.

It raise a few possibilities but two are most probable:

1) S4 is not behaving like windows 2008 enough so that client thinks 
that it is not a real windows 2008 and so it don't send this attibute.
2) This attribute is not sent by the client it's just the server that 
based on some algorithm (ie. if os.version >=6.0 and os.name contains 
"Windows" then set msDS-SupportedEncryptionType)

Can you indicate us if one of the two possibilities are the right one. 
If not please indicate the correct one.
If yes please do not forget for the case 1 to indicate what exactly 
trigger the sending of this attribute (or what block the transmission)
or if it's case 2 then give us the good algorithm.

In any case I can only reiterate the request of Andrew about pcap 
formatted  network  trace with packets which are significant (ie those 
holding this attribute).

Best regards.
Matthieu Patou.

On 08/20/2009 02:16 AM, Andrew Bartlett wrote:
> On Wed, 2009-08-19 at 09:41 -0700, Sebastian Canevari wrote:
>> Hi Andrew,
>> The msDS-SupportedEncryptionTypes attribute is populated at object creation time by the subjects that support the property.
> So it is modified over LDAP by the Windows Vista (for example) domain
> member?
>> It is also updated whenever there's a change on the object's
>> configuration that require an update of the property.
> So if the domain member upgrades, it is expected to reach out and update
> this property using LDAP?
> Are there any ACL considerations to be aware of here?  Are there any
> other restrictions on the values clients might populate here?
>> Meaning that when a subject changes the type of encryption it
>> supports, it modifies this attribute to reflect the change.
> Any chance you can provide an annotated (ie, with a separate document
> mentioning frame numbers) PCAP-formatted example network trace and
> documentation references to support this?  I would really like to pin
> this down firmly before the next alpha, now that I've turned on the
> Windows 2008 functional level and therefore AES encryption in our DC.
> Thanks,
> Andrew Bartlett
> ------------------------------------------------------------------------
> _______________________________________________
> cifs-protocol mailing list
> cifs-protocol at cifs.org
> https://lists.samba.org/mailman/listinfo/cifs-protocol

-------------- next part --------------
A non-text attachment was scrubbed...
Name: [MS-KILE]
Type: application/pdf
Size: 109788 bytes
Desc: [MS-KILE]
URL: <http://lists.samba.org/pipermail/cifs-protocol/attachments/20090828/a4a1db39/attachment-0001.pdf>

More information about the cifs-protocol mailing list