- Predrag TASEVSKI
A computer network, or in other words simply a network, is a collection of computers and other hardware components interconnected by communication channels that allow sharing of data, resources and information . Adopt for both_ private or public needs, which are used in everyday tasks to conduct transactions and communications among individuals, business, government agencies, etc. The network consists of nodes, which are individual user computers (client terminals), and one or more servers and/or host computers. Which are linked by communication systems, some of might be private, for example company, and other which might be open to public access. Obvious example of a network system that is open to public access is the Internet, where indeed, many private networks utilize publicly accessible communications, as well. Nowadays for instance, company host computers can be accessed by their employees whether in their offices over a private communications network, or from their homes, or while there on the road.
It is therefore, network security involves all activities that individuals, organizations, enterprises and institutions are undertaking to protect their value and on-going employment of assets and the integrity and continuity of operations. For that reason this article will introduce the readers and end users with the history of network security. Furthermore, with an introduction of effective network security strategy requires and most common network attacks methods. Please bear in mind that in fact, this article is not going to discuss over the depth details, rather than is going to deliver you introductory knowledge and suggestions for further perusal. And finally, we will finalize the article within conclusion.
Securing information over a network had its roots in the late 1960s when networks only existed in the sense of huge mainframes and multiple networked terminals. Hundreds of thousands and millions of dumb terminals were connected via hubs and concentrators to the huge central processing units, spinning tapes, and rotating drives in some distant air-conditioned, properly humidifier windowless room . Without the presence of client-server network models, sharing or multi-user, multi-tasking processors, network security was not yet a real concern. Network security, however, has evolved over the years due to the increasing reliance on public networks not to disclose personal, financial, and other restricted information . Such as, there are numerous instances Kevin Mitnick  and Vladimir Levin  cases that prompted organizations across all industries to re-think the way they handle information, including its transmission and disclosure. The popularity of the Internet was one of the most important developments that prompted an intensified effort in data security .
A growing number of people are using their personal computers to gain access to the resources that the Internet has to offer. From electronic email, commerce transactions and research interests, the Internet has taken place as one of the most important development of 20th century. However, the Internet Protocol (IP) in early stage was not designed to be secure. There were no approved securities standards build into the Transmission Control Protocol (TCP) and IP communication stack, which allowing it open to potentially malicious users and processes across the network. Where modern developments have made Internet communication more secure, yet there are still incidents that gain eminent attention and alert us to the fact that nothing is completely safe and secure.
Where in early 2000 a different type of attacks were unleashed on several of the most heavily trafficked site on the Internet, such as, yahoo.com, cnn.com, amazon.com and many others. Furthermore, in 2007, a data breach exploiting the widely known weaknesses of the Wired Equivalent Privacy (WEP) wireless encryption protocol resulted . Indefinitely all those incidents have granted billion of records and money to end up in the behalf of the thief.
Therefore, these results enforce the reality that computer and network security has become a quantifiable and justifiable expense for IT budgets. Organizations that require data integrity and high availability elicit the skills of system administrators, developers, and engineers to ensure 24×7 reliability of their systems, services, and information. Falling victim to malicious users, processes, or coordinated attacks is a direct threat to the success of the organization, as well as individual .
System and network technology is in fact a key technology for a wide variety of applications. Security is crucial factor to networks and applications. Although, network security is a critical requirement in emerging networks, there is a significant lack of security methods that can be easily implemented .
There is an existing communication gap between the developers of security technology and developers of networks. When considering network security, it must be emphasized that the while network is secured. Moreover, network security does not only concern the security in the computers at each end of communication sequence. Also when transmitting data the communication channel should not be vulnerable to attack. A hacker could target the communication channel, and could obtain the data, and decrypt it and re-insert a false value. In fact, securing the network is just as important as securing the computers.
As a result when developing a secure network, the following need to be considered :
Access – authorized users are provided the means to communicate to and from a particular network
Confidentiality – Information in the network remains private
Authentication – Ensure the users of the network are who they say they are
Integrity – Ensure the message has not been modified in transit
Non‐repudiation – Ensure the user does not refute that he used the network
Moreover, an effective network security plan is developed with the understanding of security issues, potential attackers and attacking methods, needed level of security, and factors that make a network vulnerable to attack. The different attacking methods are followed throughout this article endeavour.
Common Network Attacks Methods
Whiteout implemented security measures and controls in place, your network and data might be subjected to an attack. Some attacks for instance could be passive, meaning that information is monitored; other could be active, meaning the information is varying within intent to destroy or corrupt the data or the network itself.
Likelihood your networks and data are vulnerable to any of the following types of attacks if you do not have a security plan in place :
- Eavesdropping – Interception of communications by an unauthorized party
- Data Modification – Data altering, reading from unauthorized party
- Identity Spoofing (IP Address Spoofing) – IP address to be falsely assumed— identity spoofing and the attacker can modify, reroute, or delete your data
- Password-Based Attacks – By gaining your access rights to a computer and network resources are determined by who you are, that is, your user name and your password
- Denial-of-Service Attack – Prevents normal use of your computer or network by valid users, and it could be used for sending invalid data to application, to flood the computer, block traffic, etc.
- Man-in-the-Middle Attack – Is when someone between you and the person with whom you are communicating is actively monitoring, capturing, and controlling your communication transparently
- Application-Layer Attack – It targets application servers by deliberately causing a fault in a server’s operating system or applications and the attacker gaining the ability to bypass normal access controls
- Anyhow, this is just a most commonly known network attacks methods, and indeed there plenty of more.
That is why network security is an important field that is increasingly gaining attention as the Internet usage increases. The security threats and Internet protocols were analysed to determine the necessary security technology. However, the current development in network security is not very impressive and significant.
Therefore, researchers and scholars are rapidly evolving in developing and investigating the threats further in a future. And with this information in mind, the process can be formalized and the path becomes clearer as you delve deeper into the specifics of the security process, as well.
 Computer network definition. Link  Stallings, William, Internet Security Handbook, IDG Books Worldwide, Inc., 1995.  RedHat, Inc, Chapter 1. Security Overview. Retrieved from link  Kevin Mitnick Case: 1999 – No Bail, No Computer, Hacker Pleads Guilty. Retrieved from link  Vladimir Levin. Retrieved from link  Dan Goodin, May 2007. Lax security led to TJX breach. Retrieved from link  Bhavya Daya, Network Security: History, Importance, and Future.  Dowd, P.W.; McHenry, J.T., “Network security: it’s time to take it seriously,” Computer, vol.31, no.9, pp.24‐28, Sep 1998  Common Types of Network Attacks. Retrieved from link