Need help with remote access solution

Have a question or want to start a discussion? Post it! No Registration Necessary.  Now with pictures!

Threaded View


Im looking for a solution to handle remote access at our company. We
support systems that we have at customers. These systems would be for
example baggage handling systems, with PLC's, HLC's, servers etc.
In short a wide variety of clients. Because the machines are in the
customers network we need access to the machines remotely. We used to
do this by placing a VPN server device at the customers side and
connecting to that so we could access our part of the network behind
it. However many customers do not want a device in their network with
incoming connections that they dont control.

So we are looking for a solution where there are no incoming
connections at the customer, but rather the opposite: a client at the
customer LAN connecting towards a VPN server at our LAN. Outgoing
connections are usually less of a problem.

Something like below:

<a href="http://s209.photobucket.com/albums/bb25/ScartoICN /?
action=view&current=Drawing1-1.jpg" target="_blank"><img src="http://
i209.photobucket.com/albums/bb25/ScartoICN/Drawing1-1.jpg" border="0"
alt="VPN Drawing"></a>

The idea is that our LAN and the customer LAN are somehow connected
(with VPN?), ensuring that Client 1 can directly access client 2 and
support it remotely, or client 1 to 3, same idea.

One problems is that client 2 or 3 could be a PLC, which means you
cant directly access it. You need to be able to connect towards it
with special software available on client 1, hence the direct access
is important.

Could you place some sort of device in the place of the "?????" on the
drawing that connects towards the VPN device and then routes the
incoming traffic client 1 sends over the VPN tunnel towards the
clients behind it (client 2, 3 etc)?

Im really drawing a blank on how to solve this.

Thanks!

Re: Need help with remote access solution


The correct link for the drawing:

http://i209.photobucket.com/albums/bb25/ScartoICN/Drawing1-1.jpg

Re: Need help with remote access solution


I can imagine that clients are not pleased with a VPN. Anyone that has VPN
access will basically have an external computer attached to their internal
LAN. This can impose major security problems and I would never recommend it.

There are solutions where a computer at the client has an outgoing
connection to the internet. Across that connection you can establish
connections backwards to the customers network to internal devices.

We use this to perform remote support to servers, workstations, printers and
all other networked devices at our customers. We even have solutions where
both sides have no incoming connections at all and we do not know each
others IP address!
You can find a brief description of this solution here:
    http://www.nethelp.nl/RemoteSupport.gif

This method could be used in your situation, but you need a computer at the
customer that has outgoing internet access (this is your ?????).
No computing power is required, so it could be a small box that doesn't even
looks like a computer. We use fan-less mini computers that draws only 15 to
20W of power. This computer acts as a router for all your communication
protocols and provides strong encryption accoss the internet.

What communication protocols do you need to access systems at the client?
For how many customers do you need this remote access?

If the number of customers is low, youou could install all remote access
software on a computer at the client and provide remote access to this
computer. This requires a more expensive computer system and may cause
licensing problems, while every software installation may require a license
for the remote control software.

Frank





Re: Need help with remote access solution


FD wrote:
Quoted text here. Click to load it

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.



j.

Re: Need help with remote access solution


Quoted text here. Click to load it

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






Re: Need help with remote access solution


FD wrote:
Quoted text here. Click to load it

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.

Re: Need help with remote access solution



Quoted text here. Click to load it

You are not getting it completely. Still just thinking about VPN's, huh?
It's better to think about 3 proxy servers for which you do not know the
communication protocol for.

The Remote Support Server is only required when incoming connections at the
customer are not allowed. Either because of corporate policy, third party
firewalls/routers that cannot be touched or missing coorporation of an IT
department. Otherwise the helpdesk could connect directly to the Remote
Support Client, which only requires a single TCP port forwarded in the
customer's firewall.
Nobody knows how to setup a connection to the Remote Support Client. It has
a non-standard communication protocol with multiple encryption and
negotiation methods. A small program is required to setup a connection, that
will act as a proxy server and starts the client software at the helpdesk.
User authorization only gives access to the Remote Support Client. Usually
devices at the customer have additional security methods, like encryption
and authorization.



Re: Need help with remote access solution


FD wrote:
Quoted text here. Click to load it
OK, I get it. Security by Obscurity. Thanks but no thanks.

j.

Re: Need help with remote access solution



Quoted text here. Click to load it

We gave the source code of the helpdesk program to 3 hackers and they did
not manage to establish an authorized connection to the Remote Support
Client via the Remote Support Server. So obscure is a much better word than
obscurity.



Site Timeline