Computer Network Security

serversAn important aspect in computer networks is security. Network security is an art of transferring messages to make them secure and less prone to attacks. Computer security on other hand is the art of preventing unauthorized access blocking virus programs that attempt to destroy the data. In this article we have tried to address both the aspects.


Anything that prevents users from accessing the required resources for performing their task is known as threat. Threats not only include hacking of the server but it also includes bad configuration, viruses and unintentional corruption of data by the users. Thus, threats can be broadly classified into two groups, Internal and External threats.

Internal Threats:

Internal threats are wrong practices done by the users in the network resulting in inefficient working of the network. Most of the time the security violation does not happen from an outside source but it originates with an organization intentionally and unintentionally. The common internal threats are:
Unauthorized access: When a user accesses the network resources where he is not granted access, it is known as unauthorized access. It may not cause any harm to the data, but the user should not access those data. For e.g. the user is reading the employees personal files. Once the user gets access to a particular file then he may edit or delete that file which is to be protected.

Data destruction

Data destruction can be erasing or corrupting data intentionally or accidentally. Consider the case where users are authorized to access certain data but they are not authorized to make any changes to the data. For e.g. an employee may have access to the product database where he can make changes to the product description. But he discovers that he can make changes to the product prices as well. These types of threats are mostly dangerous as users are not informed about the extent to which they can modify the data.

Administrative Access

The Network Operating System comes equipped with various administrative tools and functionality. It helps to perform the various functions of the network. But giving administrative/supervisory or root access to a user can lead to problems. For e.g. giving rights to a user to delete and add files in an important folder. Hence, it is necessary to protect administrative functions and programs from access and misuse by the users.

System crash/Hardware failures

Like any other technology, even computers can fail. The main causes of computer failure can be hard drive crash, server lockup and power failure.


The most efficient and fastest method of transferring computer viruses among systems is through the network. Though most of the users focus on the virus attacks from internet, large number of viruses enter the system through USB drives, CD’s and DVD’s.

External threats:

External threats can exist in two forms. First, the attacker can manipulate your users to gain access to the network, a process called social engineering. In the second case, the hacker at a remote location can use technical drawbacks of your network to gain access. The common external threats are:
Social Engineering: Majority of attacks come under social engineering where the person manipulates the people within the organization to gain access to the network from outside. The hackers use organizational people to gain unauthorized information. The information can be network login, credit card number or any other useful information that an organization may not want that an outsider to know. Some of the social engineering attacks are infiltration, telephone scams and physical thefts.
Hackers: In Hacking, the hacker gains access to the network or computer with the help of internet worms and other hacking tools. The main objective behind hacking is to try and get into public and private networks where they have no business. The Hackers can be classified into four categories inspectors, interceptors, controllers and flooders depending upon their intentions.