Businesses need to provide their users with a method for securely
connecting to their networks while minimizing the costs associated
with providing this service - and also providing end users with
as much convenience as possible.
As businesses embrace Web services as the method for delivering their
applications, they are struggling with security issues. Network World
recently reported that the top worry for IT executives deploying Web
services is security. SSL (Secure Sockets Layer) can provide a viable
alternative to Virtual Private Networking (VPN) companies for
securing Web services.
Remote Access
Originally, remote end users connected to their corporate networks
using dial-up modem services over POTS (plain old telephone service).
This essentially provided businesses with a private connection to an
end user, albeit temporary in nature. The primary security concern
was one of authentication of the end user - guaranteeing that the
business was letting the right people access the network through its
modem pool.
As the Internet became ubiquitous, businesses longed for a way to
eliminate the long-distance charges generated by their dial-up remote
access services. End users were dialing into their ISPs locally to
access the Internet with no long distance charges - why not just let
them access the corporate network via the Internet? The simple answer
was security. VPN companies came to the rescue.
VPNs
VPNs typically put specialized software on the client machines as
well as a machine acting as the gateway to the corporate network.
These pieces collaborate to encrypt traffic between the end points,
guarantee the identity of the remote users accessing the corporate
network, and guarantee that end users connect to the right place.
Businesses can enjoy the savings of eliminating long-distance charges
while maintaining the security of a private connection.
There is, however, a downside. The specialized software that has to
go on the client machine costs both time and money. The client
software itself must be purchased and installed on every client
machine that will be enabled to access the corporate network. Anyone
who's been involved in these rollouts knows that words like
"incompatible," "conflicting programs," and "pilot error" make the
cost of deploying this crucial service much higher than simply the
price of the software at the end points - especially when dealing
with thousands of remote users.
SSL
The Internet, of course, was (and is) growing by leaps and bounds.
But consumers at large were wary of sending their credit card
information over the Internet and being defrauded. SSL was
popularized as a method to eliminate this concern. As long as the
little lock or key icon popped up in the end user's browser, he or
she felt more at ease and willing to conduct transactions over the
Internet.
Originally, SSL delivered two basic functions:
- It allowed the browser to be certain that the site being
connected to was genuinely the one requested (by using a form of
authentication).
- It secured the data that was in transit between a browser and
a Web server by using encryption.
SSL allows end users to guarantee the identity of the server to which
they're connecting. Certificate authority (CA) companies such as
VeriSign sell certificates that are installed on the SSL server. The
CA acts as an objective third party that forces the business
requesting the certificate to prove its identity prior to being
granted a certificate. End users or browsers can verify that the SSL
server to which they're connecting has a valid certificate issued by
a CA and actually belongs to the business to which they're attempting
to connect using SSL. Finally, certificates are the mechanism used to
associate a unique key used for encryption with a particular SSL
server.
The browser and server exchange keys in order to be able to negotiate
an encrypted session. SSL then encrypts data while it's flowing
between the end user and the SSL server to secure the traffic while
it's in transit.
These functions have been crucial to the success of online business.
Without them, end users wouldn't have the peace of mind needed to
share information required for completing business transactions over
the Internet.
So Why Not Just Use SSL Instead of VPNs?
Every system that's used to connect to the Internet has the client
software installed, by default, as SSL into every browser. End users
are familiar with it. SSL is a widely adopted standard. There's no
cost for the client software. There are no integration issues on
either the client or corporate network side. So what's missing?
The majority of the SSL benefits discussed have been end
user-centric. In order for SSL to be successfully used as a viable
alternative to VPNs, another element is necessary - essentially, a
method to control which clients are allowed access to the corporate
network. The SSL-based solution must be able to guarantee the
identity of the end user attempting to access the corporate network
and decide whether he or she is allowed access. This can be
accomplished using client certificates. The company can simply act as
its own CA and have end users download certificates. This allows
coverage of the basic security tenets: "who you are" (typically a
user ID), "what you have" (in this case a valid company-issued SSL
certificate), and "what you know" (a password).
This method allows the company to guarantee that only end users with
valid certificates are able to access the network. The authentication
must occur at a gateway point prior to the remote user's actually
gaining access to the network. The key is having a gateway solution
that allows a business to enforce these policies easily. With that in
place, we have the security issues addressed - encrypted traffic
between the end points, guaranteed identity of the remote users
accessing the corporate network, and a guarantee that end users are
connecting to the right place - all without the cost or
administration problems associated with VPN solutions.
Coexistence
While the SSL solution works perfectly to secure Web services or
Web-enabled applications and address the concerns expressed by IT
executives, VPN technologies provide a few things that SSL can't -
dictating that the technologies coexist. VPNs provide a solution for
applications that aren't Web enabled, such as client/server-based
applications, print services, and general file sharing. While SSL can
certainly address downloading files through a browser, there isn't a
solid solution for the other two applications at this time.
Businesses now have the opportunity to supply an SSL-based solution
to the 80% of their user population that likely uses only 20% of the
applications available (VPN services will continue to be required for
the other 20% of the population). This shift will result in
tremendous savings for businesses in terms of both time and money
through:
- Elimination of costs associated with specialized client software
- Reduced help desk calls
- Lowered demands on IT
- Increased ease of use for remote users
Conclusion
Not exactly "adios VPNs, hello SSL." But as businesses embrace Web
services through such efforts as Microsoft's .NET strategy (and
J2EE-based platforms for Web services) and the Web enabling of most
major business applications available now or within the near future,
IT executives will be able to say "adios" to VPNs for a greater
percentage of their end users and enjoy the bottom-line benefits as a
result.
Reference
Fontana, John. (2002). "Top Web services worry: Security."
www.nwfusion.com/news/2002/0121webservices.html?docid=7747
Author Bio
Jeff Browning is a product manager at F5 Networks, Seattle. F5 is a
leading provider of integrated products and services that manage,
control, and optimize Internet traffic delivery.
j.browning@f5.com
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