From: jcfmasters@yahoo.com
FD wrote:
> "jack" schreef in bericht
>> Nice solution, but what makes it different (from a security point of view)
>> from having a VPN connection into the client's network? The support
>> workstation still has full access to anything on the client's network,
>> only limited by what the intermediate server allows. And that server is
>> outside the client's control.
>>
>> What we normally do is declare all systems that have to be remotely
>> accessible for maintenance a separate DMZ, and have a firewall (under
>> client's control) between that and the rest of the network. Only what is
>> absolutely needed for operations is allowed through that firewall.
>>
>> Remote access can be via a modem, via a VPN into the DMZ, or by any other
>> means. Most IT departments are quite comfortable with that; some of the
>> more paranoid ones have the incoming VPN connection set up so that only
>> certain IP addresses are reachable through the VPN.
>>
>
> The Remote Support Server/Client have to be configured for each individual
> protocol and device that needs to be accessable.
> To create a connection the helpdesk needs a special application with
> username/password for setting up a connection with the Server and being
> switched to the Remote Support Client.
> This is the only way to make connections. No other devices in the customers
> network are accessable, which is the case with a VPN.
> The customer has an overview of all connections that the installed Remote
> Support Client supports.
>
> VPN connections can be restricted via DMZ, but most IT departments and even
> VPN suppliers have problems implementing it properly. In larger companies it
> is very difficult to get any approval to modify a router, let alone a
> firewall, so we cannot touch existing security systems.
> I have experiences where VPN and firewall suppliers did not believe our
> system works, because their security was so good. How ignorant and dumb can
> they be?
>
> This system requires no computer, network or firewall modifications. Just a
> black-box at the customer and an 1MB application at the helpdesk. It is not
> only used for remote support applications, but also for remote access like
> Microsoft's Remote Desktop (RDP). Several agencies use this to add an extra
> layers of security upon RDP: extra encryption and compression, extra
> authorization layer with access restrictions and most appreciated: Windows
> Servers need no incoming internet connections so they are less vunerable to
> attacks.
>
> Our application has extensive security measures located at the Remote
> Support Server. They are not based on IP addresses (that can be spoofed or
> are not fixed by load-balancing). We use two forms of encryption and a
> custom negotiation protocol to establish a connection, followed by
> authorization of user (helpdesk) and hardware (Remote Support Client).
>
> Frank
>
>
Thanks, that's how I interpreted the diagram you posted. In other words,
no need for the 'support server', the same functionality can be built
using just a simple black-box running some minimal Linux or BSD distro.
Place the box inside the client's LAN, make it accessible from the
outside through certificate-authenticated VPN, and give it strict
outgoing firewall rules.
The client has to trust that the ruleset that is shown to him is
actually the ruleset that the box implements. And as soon as the ruleset
includes even one RDP or VNC link to an internal server, all bets are
off anyway and anybody with the support password/cert can use that as a
stepping stone to other systems.
j.
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