Security in Computer Networks - Research Paper Example

Security in Computer Networks Millions of computer users across the globe today are exposed to the Internet that has raised safety concerns with respect to personal data and information. The use of computers for online banking and monetary transactions as well as communicating with friends and associates online has left the users vulnerable to hackers and spywares. Apart from the Internet that is the largest public data network there are private networks such as Wide Area Networks (WANs) of companies connecting their offices located remotely as well as billions of Local Area Networks (LANs) within the premises that connect computers in a local environment. The paper provides a broad discussion on threats to security in computer networks and techniques used as control mechanism. The discussion provides a comparative analysis of these control mechanism and their relative effectiveness in implementing computer network security. Introduction Computer security is the "protection afforded to an automated information system in order to attain the applicable objectives of preserving the integrity, availability and confidentiality of information system resources (includes hardware, software, firmware, information/data, and telecommunications)" (NIST, 2008). Some of the threats facing the computer networks include spywares, viruses, and hacking codes or programs that expose the users to potential dangers of data loss and fraud activities. Most of the computer users are unaware of the dangers or potential abuse related to these applications and can cause extensive damage or increase the chances of fraud or identity theft or damage to the computer systems and files. It is a challenging task to prevent cyber crime owing to the unlimited expanse and use of Internet that provides extensive scope to fraudsters. Programs like spyware, adwares, viruses or hacking software can be prevented from being downloaded into the computer system through the use of firewalls, adjusting browser settings and installing anti-spyware protection applications. There are many techniques and protocols devised and are in use to protect or secure the computer networks and the data traveling through the network. Depending on the security policy of the computer network one can choose and deploy the security protocols at different layers of the network. The extent to which a computer network is secured depends on the encryption technology and the algorithm used to do the authentication. Comparison of different protocols and architecture Transmission Control Protocol over Internet Protocol (TCP/IP) and Open System Interconnection (OSI) are two protocol models widely used in the network architecture. Firewalls are the techniques that are employed within the network to protect it from the external security threats. The firewall can be deployed through a hardware device with preloaded firmware connected within the network as well as it can be a deployed through software system working purely based on the set of algorithms or it can be a combination of both. Secured Socket Layer (SSL) is used to secure the transfer of data / authentication information over the network. This technique uses the good combination of private key and public key cryptography for securing the data over the network. This works over and above the TCP. Virtual Private Network (VPN): Establishing a protected network between two secured network services or nodes located in two separate protected networks but is separate by unprotected channel or network. For the purpose of explaining the security mechanism in computer networks the paper focuses on TCP/IP and OSI models followed by a comparative analysis with other techniques. Implementation details In TCP/IP model the media transmission happens through five layers. Application layers, network layers and transport layers are the part of software layer in the network. Data link layers and physical layers are the part of physical layer in the network. Physical layers are mainly data-link cables and signals. The chart below depicts the sequence of media signals in the TCP/IP protocol. (Source: Wang J. 2009) In OSI model bottom layer is the physical layer followed by the data link layer and then the network layer. All these three layers are in the lower level of the network. After the network layer there is the transport layer followed by the presentation layer and on top is the application layer. All these four layers are in the upper level of the network. The OSI framework for deploying protocols in a network environment is based on open source architecture but it is not made as a standardized framework. So in today's architecture of all the network OSI model is used as a reference. In most of the networks one or combination of many OSI models are used. Analysis and results When network engineers deploy the security at the application layer it gives an end to end protection and there is no need for data decryption and verification of signature. But it is vulnerable to hackers because they can change the header information. To overcome the above said vulnerability, security is deployed through encryption at the transport layer. This gives security to the Transmission Control Protocol (TCP) at the packet level and there is no need to do any change the in the application software. But still the attackers can do damages by analyzing traffic by recognizing the IP address. This type of security lapse can be overcome by encrypting the data at the network layer. It provides link-to-link security in the network. It can be deployed in transport mode as well as in tunnel mode. For tunnel mode deployment a gateway is required and this too does not require any changes in the application program. Comparison with other techniques The hardware firewall is the more secured option for protecting all areas of the network that are based on TCP/IP protocol. The firewalls are the fast security that can be deployed in the network to securely allow the users to enter and be in the network as well as allow the data transfers based on the pre-defined hierarchy and policies set by the organization without any abnormal delays. It allows only the authenticated users to enter into the network. It also uses various filter techniques to apply the security and data sharing policies of the organization. The firewall disallows the unauthorized user to enter in the network, it disallows the unauthorized transfer of data and it maintains the users' behaviors by logging in the entire activities of all the users within the network. Various software programs are used to protect the network, computers and the data from the attacks of Viruses, Trojans, Malware, Spyware and suspecting programs. This is also called the anti virus scanners and detectors. These are antidotes developed developed by software companies who keep upgrading the programs based on new threats or viruses generated. The anti virus software programs are installed in the network through the server as well as in the client-PCs. The system administrator monitors the anti virus program and updates the system on a regular basis. The system administrator also makes sure that each node-pc in the network has the update of the anti virus program in it. Presently there are intelligent anti virus program that does the system administrator's job automatically on its own based on the pre-defined schedule and schema. The SSL uses the shared session keys. Through the use of shared session keys the data is encrypted and decrypted at the client side and the server side. It is a single layer security. In SSL the identity authentication at both side (i.e. client and the server) happens through the use of digital signature. The client side sends randomly generated data string, SSL version number and encryption algorithms to the server and the server verifies it and send the same details to the client along with the digital signature, the client side decrypts the digital signature and there is a common key maintained. After the entire verification process happens and in case all details matches then only the transaction takes place. The VPN provides secured encrypted sessions between the nodes that are connecting themselves outside its own secured network. It means when using a VPN it creates a private channel between the nodes. This method is very cost effective for achieving the benefits of a private network in a non-private network environment. But there are many disadvantages in securing a network through VPN. It increases the cost of encryption, decryption and storage overheads over the period of time. The VPN if not designed properly it may increase the packet processing thus reducing the network performance. Conclusion There is no single technique or technology that can serve all needs of the network security. There has to be mix of various techniques and technologies at various level and places of the network to protect it from external as well as external security threats and vulnerabilities. Different network behaves differently hence the policy and framework for security needs to be designed exclusively and the security devices and security programs should be made as part of the network system itself. References: 1. NIST. (2008) An Introduction to Computer Security: The NIST Handbook. National Institute of Standards and Technology - US Department of Commerce. Retrieved from http://csrc.nist.gov/publications/nistpubs/800-12/handbook.pdf 2. Banerjee, Rahul. (2006) Of More Cryptographic Algorithms & Network Security Systems. Lecture-4. Retrieved from http://discovery.bits-pilani.ac.in/rahul/NetSec/Network%20Security-Lecture-4-2005-2006-secure.pdf 3. Wang, J. (2009) Chapter 5- Network Security Protocols in Practice. Part I. Retrieved from http://www.cs.uml.edu/'wang/NetSec/Chapter_5_part1.ppt 4. CISCO Systems. (2001) A Beginner's Guide to Network Security. Retrieved from http://www.cisco.com/warp/public/cc/so/neso/sqso/beggu_pl.pdf 5. PC Mag. (2009). Definition of TCP/IP. Retrieved from http://www.pcmag.com/encyclopedia_term/0,2542,t=TCPIP&i=52614,00.asp 6. PC Mag. (2009) Definition of OSI. Retrieved from http://www.pcmag.com/encyclopedia_term/0,2542,t=OSI&i=48641,00.asp 7. Misra, Christopher. (2007) Security Architectures. University of Massachusetts. Retrieved from http://security.internet2.edu/docs/cmisra-architectures.pdf Read More