Today we live in a connected world. Communication is a
key requirement for all systems. Increased integration of
systems requires a compulsive need to establish fast and
reliable communication that is as widespread as the organization
and its business dealings. Information systems need to reach out
to users, vendors, customers and partners (irrespective of their
location); everything is connected to nearly everything else.
All this brings us to the issue that looking at any system as
something that is inside one box or in one enclosed space is
not enough to gain assurance about its security. The reality is
that nearly every computer in the world could be, and in most
cases is, connected to every other computer through the
Internet. The worldwide propagation of the (in)famous Nimda,
Code Red and Lovebug viruses and worms are proof of this
connectivity. Such connectivity has the propensity to provide
access or communication paths for anyone to any system in
the absence of any measures to prevent such access.
Fortunately, a plethora of technical solutions, many of which
have become standards, keeps most networks and systems
segregated and protected.
Therefore, let us look at how we fashion an approach to
auditing networks and ensuring that they are secure.
It is also good to emphasize at this stage that in the overall
information systems audit framework, the audit of networks is
one piece of the puzzle, with the other notable pieces being
audit of application software, audit of operating systems and
databases, audit of physical and environmental security and
audit of business continuity (these have been dealt with in
earlier issues of the IT Audit Basics column). To obtain a
comprehensive assurance about systems, it is important to
assess and evaluate all the parts. In this issue, we will focus on
auditing network security.
A network could be as simple as a small local area network
(LAN) connecting a few computers inside a single room or a
building, or it could be something that connects computers at
factories and offices spread over a number of cities or even
countries. A network could also be connected to other networks,
such as the networks of customers or vendors or a public
network like the Internet.