Why Implement Network Security?

A long time ago in a galaxy far, far away, computers were standalone and did not talk to one another. There was such a thing as SneakerNet. What is SneakerNet? SneakerNet was saving files onto a 5.25" floppy disk or other removable media and handing that media to your co-worker. Bam! ”the network was born. Today, computers are connected throughout the world via high-speed and low-speed connections. You can jump on your computer in Dallas and instantaneously be connected to Tokyo or Moscow. What does this all mean to you as a network-security engineer? Everyone who's connected to the Internet also has connectivity to you. Just like the world in general, the Internet has good folks and bad folks. The good folks legitimately want to access information that you have available. The bad folks want to access information they shouldn't, change the information that you have available, or, at worst, delete or even steal your hard work. Stealing your corporate confidential information is the most desirable for your competitors .

For example, a database with your customers and all related information (services, cost, and so on) might be very attractive to them.

Today, corporations rely on connectivity not only to sell products and services to consumers but also for business-to-business transactions. Think about just-in-time inventory control. Companies only stock manufacturing goods for that day's manufacturing run, and throughout the day, they update their suppliers with information so they can plan their production processes. If a hacker can manipulate either the data sent to suppliers or the computers at the supplier's location, he can have a serious impact on the manufacturing process, which could result in the loss of millions of dollars per day per organization. The bigger the organization, the bigger the potential loss. That's why network security is extremely important today: because of the business impact that connectivity options have created.

Classification of Networks

There are two different types of networks: the old network type and the new network type. The old network type is the closed network. The closed network connects only known providers and known sites without connecting to any public networks. Because the company is not connecting through public networks, we can be reasonably assured that the network is secure.

Today's network is the open network type. Not only do we have connectivity to the Internet from the corporation, but we also rely on connectivity through an Asynchronous Transfer Mode (ATM) network, leased lines, and Frame Relay networks. We also have users connecting to corporate resources via the Public Switched Telephone Network (PSTN). All these different connectivity options result in a network that is wide open for potential hackers and results in the corporation investing resources to secure the network from outside attacks.

Importance of Security

Along with the open network, individuals have gained technical expertise in programming and the knowledge of how communication protocols work as well as how to exploit them. It is easy to get a book or gain the knowledge from the Internet on how to program in C or C++ and write relatively sophisticated programs. The Internet provides a wealth of information, and individuals like to post their code and applications for others to enjoy.

What Is a Network Security Policy and Why Do We Need It?

Because today's business needs 24/7 connectivity to the Internet and the need to provide high availability for network resources through Internet, the Internet Engineering Task Force (IETF) has RFCs on security, one of which is RFC 2196, "Site Security Handbook." RFC 2196 states that "a security policy is a formal set of the rules to which people who are given access to an organization's technology and information assets must abide." We can also think of a security policy as implementing a corporation's policies for users' access to corporate resources and rights allowed within the corporate computing environment.

Corporations need to create a security policy because they are the rules by which users need to live. We can't live by unwritten rules. A corporation's security policy should contain such things as what is allowed and what is not allowed, what resources can be accessed within a company by what particular users, and what resources users cannot access. Also, a security policy serves as your ”the network security administrator's ”framework for implementing security within your computing environment. One of the benefits of a security policy is that it is communicated throughout the organization and helps foster consensus and define roles within the organization.

Contents of a Security Policy

Some of the key components of a security policy are an acceptable use policy, an access policy (such as Internet access, campus access, and remote access), incident-handling procedures, and, most importantly, a statement of authority and scope for the security policy.

Evolution of Hacking

As the sophistication of network-management applications has increased, the accessibility to these programs has also increased because of the Internet. An individual user no longer needs to write her own code. She can simply download it. You can now download extremely sophisticated " network-management " applications from the Internet for either legitimate or illegitimate purposes. With the increase in the sophistication of hacking tools, there has been an equal decrease in the need for technical knowledge. Again, with the ease of access to sophisticated applications, along with worldwide connectivity, the result is that the world is a more dangerous place.