[External] : Re: Windows Credential Guard with MSLSA

Simo Sorce simo at redhat.com
Wed Sep 6 18:09:35 EDT 2023

Are trying to forward TGTs from Windows clients to a Linux Server?

A) You shouldn't
B) I am not aware of any implementation of Credential Guard that will
allow that.

If you just need to impersonate users for some specific task there is
constrained delegation which is better than forwarding around
credentials critical for security, and allows the KDC (ie central
administration) to properly control and authorize it.


On Wed, 2023-09-06 at 21:05 +0000, Seshan Parameswaran wrote:
> Hi Sam
> Let me make it clear.
> I am using Linux Server / MIT Libraries for server and Windows Client .  Microsoft Active Directory as KDC Host.
> Scenario – 1
> Credential cache stored with MSLSA – AllowTGTSessionKey<https://learn.microsoft.com/en-us/troubleshoot/windows-server/windows-security/kerberos-protocol-registry-kdc-configuration-keys> registry setting can be used to allow the Linux Kerberos MIT library  to retrieve credential cache from KDC Host for forwardable TGTs.
> Scenario-2
> Credential cache stored with Windows Credential Guard -  Do not know of any solution that allows Linux Kerberos MIT library to retrieve cache from the Windows Credential Guard as it uses signed certificates.  Looking for a solution.
> Hope that helps.
> Seshan
> From: Sam Hartman <hartmans at debian.org>
> Date: Wednesday, September 6, 2023 at 1:58 PM
> To: Seshan Parameswaran <seshan.parameswaran at oracle.com>, krbdev at mit.edu <krbdev at mit.edu>
> Subject: Re: [External] : Re: Windows Credential Guard with MSLSA
> > > > > > "Seshan" == Seshan Parameswaran <seshan.parameswaran at oracle.com> writes:
>     Seshan> I am running on Oracle Enterprise Linux and using MIT
>     Seshan> libraries.  I am aware of the AllowTgtSessionKey Registry
>     Seshan> setting parameter that works when MSLSA is used without the
>     Seshan> Credential Guard.  My query is specific to MSLSA used with
>     Seshan> Windows Credential Guard.
> Your question doesn't make sense.
> MSLSA is not a Linux thing:
> MS -> Microsoft
> LSA -> local security authority
> The LSA exists on Windows systems.
> If you are not on a Windows system, you don't have one.
> It may be that you want to be asking about credential guard and Linux.
> But involvind MSLSA or LSA in the discussion only confuses everyone.
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Simo Sorce
RHEL Crypto Team
Red Hat, Inc

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