[cifs-protocol] [REG:118040517948537] MS-ADTS: msDS-ResultantPSO and DOMAIN_USER_RID_KRBTGT discrepancy

Tue Apr 24 16:54:13 UTC 2018

Hi Tim:
The code actually intends to not return msDS-ResultantPSO when RID is equal to that of krbtgt but due to a bug, the comparison fails and instead of nothing, the msDS-ResultantPSO is returned. I tested against WS2012R2. The code is identical from Vista (WS2008) till Ws2012R2. I have not checked against WS2016 yet. 

I have filed a bug against MS-ADTS to fix this issue.

Regards,
Obaid Farooqi
Escalation Engineer | Microsoft

Exceeding your expectations is my highest priority.  If you would like to provide feedback on your case you may contact my manager at ramagane at Microsoft dot com

-----Original Message-----
From: Tim Beale <timbeale at catalyst.net.nz> 
Sent: Monday, April 9, 2018 12:12 AM
To: Obaid Farooqi <obaidf at microsoft.com>
Cc: cifs-protocol at lists.samba.org; MSSolve Case Email <casemail at microsoft.com>
Subject: Re: [REG:118040517948537] MS-ADTS: msDS-ResultantPSO and DOMAIN_USER_RID_KRBTGT discrepancy

Hi Obaid,

You can reproduce the problem by doing the following:

- Create a new msDS-PasswordSettings object. E.g.
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fblogs.technet.microsoft.com%2Fcanitpro%2F2013%2F05%2F29%2Fstep-by-step-enabling-and-using-fine-grained-password-policies-in-ad%2F&data=02%7C01%7Cobaidf%40microsoft.com%7C9e0e2771473540762c9508d59dd85fb4%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636588475007318631&sdata=iztmo%2BfkcSggbJe%2FxTDmIA4ZW75noVaDRW%2FfRbvxA4k%3D&reserved=0
or a more out-dated approach using ADSI Edit (which I think I used
originally)
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fblogs.technet.microsoft.com%2Fseanearp%2F2007%2F10%2F06%2Fwindows-server-2008-fine-grained-password-policy-walkthrough%2F&data=02%7C01%7Cobaidf%40microsoft.com%7C9e0e2771473540762c9508d59dd85fb4%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636588475007318631&sdata=3%2FkmbCFEDopECsTsyKvtgV%2FtRNX9UBru7G5QJqbJ57c%3D&reserved=0
- Apply the PSO to the krbtgt user. I did this by opening ADSI Edit,
right-clicking on the PSO created in the previous step, select
'Properties', then edit the msDS-PSOAppliesTo attribute. I used the 'Add
DN' option and just pasted in the DN of the krbtgt user (then click
'OK', and 'Apply').
- Check the Resultant PSO. i.e. In ADSI Edit, right-click on the krbtgt
user, select 'Properties', then look for the msDS-ResultantPSO attribute.

I've actually been testing this as part of Samba development by using a
python test script that connects to the Windows DC over LDAP and does
the above steps as LDIF operations. So you can probably reproduce the
first 2 steps just by applying an LDIF (tentative example follows, but I
haven't tried using exactly this approach myself).

dn: CN=test-PSO,CN=Password Settings Container,CN=System,DC=<your-domain>
changetype: add
objectClass: msDS-PasswordSettings
msDS-PasswordSettingsPrecedence: 2
msDS-PasswordReversibleEncryptionEnabled: FALSE
msDS-PasswordHistoryLength: 10
msDS-PasswordComplexityEnabled: TRUE
msDS-MinimumPasswordLength: 10
msDS-MinimumPasswordAge: 0
msDS-MaximumPasswordAge: -25920000000000
msDS-LockoutThreshold: 0
msDS-LockoutObservationWindow: -50000000
msDS-LockoutDuration: -50000000
msDS-PSOAppliesTo: CN=krbtgt,CN=Users,DC=<your-domain>

Cheers,
Tim

On 07/04/18 08:27, Obaid Farooqi wrote:
> Hi Tim:
> Can you please let me know the step you took to add this object and applied to krbtgt?
>
> Regards,
> Obaid Farooqi
> Escalation Engineer | Microsoft
>
> Exceeding your expectations is my highest priority.  If you would like to provide feedback on your case you may contact my manager at ramagane at Microsoft dot com
>
> -----Original Message-----
> From: Obaid Farooqi 
> Sent: Friday, April 6, 2018 12:48 PM
> To: 'Tim Beale' <timbeale at catalyst.net.nz>
> Cc: cifs-protocol at lists.samba.org; MSSolve Case Email <casemail at microsoft.com>
> Subject: RE: [REG:118040517948537] MS-ADTS: msDS-ResultantPSO and DOMAIN_USER_RID_KRBTGT discrepancy
>
> Hi Tim:
> I'll help you with this issue and will be in touch as soon as I have an answer.
>
> Regards,
> Obaid Farooqi
> Escalation Engineer | Microsoft
>
> Exceeding your expectations is my highest priority.  If you would like to provide feedback on your case you may contact my manager at ramagane at Microsoft dot com
>
> -----Original Message-----
> From: Obaid Farooqi 
> Sent: Friday, April 6, 2018 12:47 PM
> To: "'Tim Beale'" <timbeale at catalyst.net.nz>
> Cc: "cifs-protocol at lists.samba.org" <cifs-protocol at lists.samba.org>; "MSSolve Case Email" <casemail at microsoft.com>
> Subject: [REG:118040517948537] MS-ADTS: msDS-ResultantPSO and DOMAIN_USER_RID_KRBTGT discrepancy
>
> Hello Tim 
>
> We have created a case; 118040517948537, to track your inquiry and an Escalation Engineer will contact you to assist further.
>
> Best Regards,
> Tarun Chopra | Sr. Escalation Engineer
> Open Specifications Support Team
> Work +1-425-705-5042
> Email  tarun.chopra at microsoft.com
> Monday-Friday 9:00a-6:00p Pacific Timezone 
>
> -----Original Message-----
> From: Tim Beale <timbeale at catalyst.net.nz>
> Sent: Thursday, April 5, 2018 2:00 PM
> To: Interoperability Documentation Help <dochelp at microsoft.com>; cifs-protocol at lists.samba.org
> Subject: MS-ADTS: msDS-ResultantPSO and DOMAIN_USER_RID_KRBTGT discrepancy 
>
> Hi, 
>
> I'm looking into the behaviour of msDS-ResultantPSO and found a discrepancy between the specification and the actual behaviour.
>
> In MS-ADTS, section 3.1.1.4.5.36 msDS-ResultantPSO [1], it says the
> following: 
>
>   If the RID in U!objectSid is equal to DOMAIN_USER_RID_KRBTGT, then there is no value in this attribute. 
>
> I tried adding a PSO object and applying it to the krbtgt user on a Windows 2012R2 VM. Based on the spec, I would expect no msDS-ResultantPSO to be returned for the krbtgt user. However, I do see one returned, e.g.
>
> # record 1
> dn: 
> CN=krbtgt,CN=Users,DC=WINDOWS2012R2,DC=WIN,DC=TIM,DC=WGTN,DC=CAT-IT,DC=
> CO,DC=NZ
> objectSid: S-1-5-21-886655096-618523297-2770022155-502
> msDS-ResultantPSO: CN=dummy-PSO,CN=Password Settings Container,CN=System,DC=WINDOWS2012R2,DC=WIN,DC=TIM,DC=WGTN,DC=CAT-IT,DC=
> CO,DC=NZ
>
> You can see the RID in the objectSid is 502, which is DOMAIN_USER_RID_KRBTGT. 
>
> Could you please clarify which is incorrect - the specification or the Windows behaviour? Or have I misunderstood something?
>
> Thanks,
> Tim 
>
> [1]
> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmsdn.mi
> crosoft.com%2Fen-us%2Flibrary%2Fcc223866.aspx&data=02%7C01%7Cdochelp%40w
> indows.microsoft.com%7Ce172420a92714a01130f08d59b383228%7C72f988bf86f141
> af91ab2d7cd011db47%7C1%7C0%7C636585588018722990&sdata=KdE0SNnF0Xy3GBjnp8
> UKzXt4GB9xQ2j0fFKuUZaD9JI%3D&reserved=0
>
>