[isapros] Re: OT: Requiring client-side certs for RDP
- From: "Thomas W Shinder" <tshinder@xxxxxxxxxxx>
- To: <isapros@xxxxxxxxxxxxx>
- Date: Fri, 13 Jul 2007 16:04:50 -0500
You can't with Server Publishing Rules because there are no listeners
available to them that will accept user credentials.
Thomas W Shinder, M.D.
Site: www.isaserver.org
Blog: http://blogs.isaserver.org/shinder
Book: http://tinyurl.com/3xqb7
MVP -- ISA Firewalls
> -----Original Message-----
> From: isapros-bounce@xxxxxxxxxxxxx
> [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thor
> (Hammer of God)
> Sent: Friday, July 13, 2007 11:54 AM
> To: isapros@xxxxxxxxxxxxx
> Subject: [isapros] Re: OT: Requiring client-side certs for RDP
>
> Hmmmm. Why I can't do that via regular publishing then?
>
> t
>
> > -----Original Message-----
> > From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-
> > bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder
> > Sent: Friday, July 13, 2007 10:49 AM
> > To: isapros@xxxxxxxxxxxxx
> > Subject: [isapros] Re: OT: Requiring client-side certs for RDP
> >
> > User cert auth at the ISA firewall will solve this problem - for TSG
> > that is.
> >
> > Send via Windows Mobile though ISA Firewall protected
> Exchange Servers
> >
> >
> > -----Original Message-----
> > From: "Thor (Hammer of God)"<thor@xxxxxxxxxxxxxxx>
> > Sent: 7/13/07 11:40:57 AM
> > To: "isapros@xxxxxxxxxxxxx"<isapros@xxxxxxxxxxxxx>
> > Subject: [isapros] Re: OT: Requiring client-side certs for RDP
> >
> > While dude's article is clearly wrong, the MSFT KB's should
> be amended
> > as well. Saying "the client must trust the root
> certificate authority"
> > is simply incorrect and misleading.
> >
> > But, more to the core question, since the ts gateway is not
> the place
> > to
> > enforce this, are there plans in place for longhorn
> terminal services
> > to
> > support client certificate requirements like IIS does?
> >
> > t
> >
> > > -----Original Message-----
> > > From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-
> > > bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison
> > > Sent: Friday, July 13, 2007 10:26 AM
> > > To: isapros@xxxxxxxxxxxxx
> > > Subject: [isapros] Re: OT: Requiring client-side certs for RDP
> > >
> > > I just love it when "tribal knowledge" becomes "documented fact".
> > > It's clear from the "article" that the author never
> tested any of the
> > > configuration or application statements he makes.
> > > Even the dialog for his "attempt authentication"
> screenshot clearly
> > > states "Authentication will confirm the identity of the remote
> > computer
> > > to which you connect" - NOT "Authentication will confirm
> the identity
> > > of
> > > the user/machine **from which you connect**".
> > >
> > > In theory you *could* require user cert auth, but I don't know if
> > the
> > > TSG client will respond appropriately. Since TSG is
> "just" RPC/HTTP,
> > > it's rpcrt4.dll that handles the translation between RPC
> and HTTP and
> > > AFAIK, it only handles Basic and NTLM.
> > >
> > > Because TSG is RPC/HTTP, you can configure the /RPC vroot
> to require
> > > user certs and thus impose this requirement on your connecting
> > clients
> > > to test this theory. Of course, if you also share this vroot with
> > > Exchange RPC/HTTP you'll break OL connections, since they can't
> > handle
> > > cert auth.
> > >
> > > -----Original Message-----
> > > From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-
> > > bounce@xxxxxxxxxxxxx]
> > > On Behalf Of Thor (Hammer of God)
> > > Sent: Friday, July 13, 2007 9:29 AM
> > > To: isapros@xxxxxxxxxxxxx
> > > Subject: [isapros] OT: Requiring client-side certs for RDP
> > >
> > > Greets:
> > >
> > >
> > >
> > > Windows Server 2003 SP1 allows one to configure
> server-authentication
> > > via certificate for RDP over TLS/SSL. The MSFT articles
> say things
> > > like "the client must trust the certificate" etc in their
> > > client-configuration notes, and other articles specify
> that you can
> > > control access to RDP by issuing self signed certs and controlling
> > > distribution.
> > >
> > >
> > >
> > > This presents the illusion that one can limit connections
> to RDP on a
> > > Win2k3 server via this method. See:
> > >
> > > http://support.microsoft.com/kb/895433
> > >
> > >
> http://technet2.microsoft.com/windowsserver/en/Library/a92d8eb9-f53d-
> > > 4e8
> > > 6-ac9b-29fd6146977b1033.mspx
> > >
> > > http://www.windowsecurity.com/articles/Secure-remote-desktop-
> > > connections
> > > -TLS-SSL-based-authentication.html
> > >
> > >
> > >
> > > Win2k3 Terminal Services allows one to require security
> levels, but
> > > only
> > > provides "server" authentication - it does not allow you
> to require a
> > > particular certification to be requested of the client
> (as IIS does).
> > >
> > >
> > >
> > > Snips from the windowsecurity article compound this perception:
> > >
> > > <snip>
> > > The threat becomes even bigger, when the server running Microsoft
> > > Windows Terminal Services is accessible from the Internet
> through an
> > > RDP
> > > connection on port 3389, even though you have an advanced firewall
> > such
> > > as ISA Server in front of it. A scenario that is common especially
> > for
> > > Microsoft Small Business Server users.
> > >
> > > The good news however, is that you can prevent these attacks. The
> > > solution is certificate based computer authentication. If the
> > computer
> > > cannot authenticate itself by presenting a valid
> certificate to the
> > > terminal server it is trying to connect to, then the RDP
> connection
> > > will
> > > be dropped before the user has a chance to attempt to log on.
> > >
> > > </snip>
> > >
> > >
> > >
> > > This is simply untrue. The client does not "present a valid
> > > certificate" at all. It either trusts the server or not,
> and it is
> > up
> > > to the client to make that decision. While RDP clients 6
> and below
> > > only
> > > allow "No auth, attempt, or require" which do provide the expected
> > > behavior, updated or alternate clients (like Vista) allow you to
> > > connect
> > > anyway.
> > >
> > >
> > >
> > > This being said, does anyone know if the current
> longhorn/ts gateway
> > > features will actually allow enforcement of client
> certificates such
> > a
> > > requiring client certs that are signed by particular authorities?
> > >
> > >
> > >
> > > Sorry for all the detail, but I wanted to avoid people
> saying "Sure,
> > > just require TLS for RDP".
> > >
> > >
> > >
> > > t
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > All mail to and from this domain is GFI-scanned.
> > >
> >
> >
> >
>
>
>
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