[isapros] Re: OT: Requiring client-side certs for RDP
- From: "Thor (Hammer of God)" <thor@xxxxxxxxxxxxxxx>
- To: <isapros@xxxxxxxxxxxxx>
- Date: Fri, 13 Jul 2007 11:20:27 -0700
You know, you're a smart dude. This will work on "creative" rules to internal
TS in the absence of TSG as well...
Rock on.
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.
> >
>
>
>
Other related posts:
