3.2 Current developmental situation of computer network security

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1 Overview on Network Security Sujata Tambat, VaibhavNarkhede ME-CSE, HOD PLIT, Buldana. Abstract- With the rapid development of computer technology, computer network continues to expand the scope of application with more and more users. Network security gradually attracts people's attention. This paper starts with the concept of computer security, elements and nature of computer network security, focuses on the threats of computer network security and discusses basic techniques. It proposes effective defence techniques to improve the computer network security. Index terms-computer network security; elements and nature; threats; basic technique; measures. 1. INTRODUCTION A computer network or data network is a telecommunications network which allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections (network links). Data is transferred in the form of packets. The connections between nodes are established using either cable media or wireless media. The bestknown computer network is the Internet. And hence network Security has become very important in today s world, as a result of which various methods are adopted to bypass it. Network administrators need to keep up with the recent advancements in both the hardware and software fields to prevent their as well as the user s data. The requirements of information security within an organisation have undergone two major changes in the last several decades before the widespread use of data processing equipment,the security of information felt to be valuable to an organization was provided primarily by physical and administrative means with the introduction of computer the need for automated tools for protecting files and otherinformation stored on the computer became an evident.this is especially the case for a shared system,such as time sharing system and the need is even more acute for systems that can be accessed for a public telephone or a data network. The generic name for the collection of tools to protect data and to thwart hackers is computer security.network security refers to protecting the websites domains or servers from various forms of attack. Network security is important in every field of today s world such as military, government and even in our daily lives. Having the knowledge of how the attacks are executed we can better protect ourselves. The architecture of the network can be modified to prevent these attacks, many companies use firewall and various polices to protect themselves. This paper outlines the various threats which are observed, as well as various defence mechanisms against them. 2. OVERVIEW OF COMPUTER NETWORK SECURITY Computer network security is fundamentally network information security. It refers to the network system that we use to preserve and flow information and data which may otherwise be exposed to accidental or 94

2 deliberate damage, leaks or changes. Generally network security is inextricably related to the confidentiality integrity, authenticity and reliability of network. Its control technologies and concepts are necessary to analyse. A network consists of routers from which information can be easily stolen by the use of malwares such as a Trojan Horses. The synchronous network consists of switches and since they do not buffer any data and hence are not required to be protected. Network security is thus mainly focused on the data networks and on the devices which are used to link to the internet. As forecasting goes for the field of the network security it can be said that some new trends are emerging some are based on old ideas such as biometric scanning while others are completely new and revolutionary. is a widely used service today and it is also contain many serious flaws, there is no system of authenticating the sender as well as the recipient, it is stored in multiple places during transmission and can be easily intercepted and changed. SPAM are serious security threat they only require very less manpower but affect millions to billions of users around the world, they can malicious link or even false advertisements. A network contains many vulnerabilities but most of them can fixed by following very simple procedures, such as updating software and correctly configuring network and firewall rules, using a good anti-virus software etc.in this report most of the basic information regarding network security will be outlined such as finding and closing vulnerabilities and preventing network attacks and also security measures currently being used. 3. CURRENT SITUATION OF COMPUTER NETWORK SECURITY 3.1 The idea security of computer network The computer network security we talk about actually is the security of computer network, security of important data in the network system and the structural completion of computer network. To accomplish computer network security is to protect users data and computer system from malicious attacks and steals from outside. People who work on protection of computer network security are technical material analysis engineer of computer network security. They protect the network system from computer security problems that would influence the security of users computers, like steal, collapse, interrupt and etc. 3.2 Current developmental situation of computer network security Nowadays, computers are popularized and became an indispensable part in people s life. People use computer network communication technology to communicate with friends, finish works, learn new knowledge and entertain themselves. The development of computer technology is changing people s way of living and improving the quality of life. However, computer network security still bothers people. It is a serious problem to China and the world. There are a lot of computer network security specialists working on in-depths researches in computer network security. They have set up special researches on the maintaining, destruction and repairmen of computer network security. Based on these research results, specialists built the PPDRR computer network security model. Through the PPDRR computer network security model, people can accomplish monitoring and analysing computer network security. Through the PPDRR computer network security model, specialist can detect the vulnerabilities of computer network system and react in time to protect computer network system from leak of information and economical loss. The designing of computer network security involves a wide range of specialties. Any professional knowledge related to computer could be involved, for example software 95

3 design of computer software development, monitoring and maintenance of software could all use the protection of computer network security. The protection of computer network security could protect developed technology and avoid economic loss. Therefore many computer network security specialists work on the design, protection and research of computer network security, hoping to find an effective method of computer network security or a way to investigate the attacker of computer network system. Through large amount of researches, specialists proposed a new analysis method of computer network security-- attack-tree. Specialists integrate past attacking data and use mathematical formulas to represent them. This kind of method is called attack-tree. Although this method still have some flaws and disagreements in integrating and explaining the leaves. Therefore some specialists also proposed privilege graph analysis method to improve past computer network security analysis methods. 4 ELEMENTS OF COMPUTER NETWORK SECURITY 4.1Secrecy Only the sender and intended receiver should be able to understand the contents of the transmitted message. Because eavesdroppers may intercept the message, this necessarily requires that the message be somehow encrypted (disguise data) so that an intercepted message cannot be decrypted by an interceptor. This aspect of secrecy is probably the most commonly perceived meaning of the term "secure communication." Note, however, that this is not only a restricted definition of secure communication, but a rather restricted definition of secrecy as well. 4.2 Authentication Both the sender and receiver need to confirm the identity of other party involved in the communication to confirm that the other party is indeed who or what they claim to be. Face-to-face human communication solves this problem easily by visual recognition. When communicating entities exchange messages over a medium where they cannot "see" the other party, authentication is not so simple. Why, for instance, should you believe that a received containing a text string saying that the came from a friend of yours indeed came from that friend? If someone calls on the phone claiming to be your bank and asking for your account number, secret PIN, and account balances for verification purposes, would you give that information out over the phone? Hopefully not. 4.3 Message Integrity Even if the sender and receiver are able to authenticate each other, they also want to insure that the content of their communication is not altered, either maliciously or by accident, in transmission. Extensions to the check summing techniques that we encountered in reliable transport and data link protocols 4.4 Nonrepudiation Nonrepudiation deals with signatures having established what we mean by secure communication; let us next consider exactly what is meant by an "insecure channel." What information does an intruder have access to, and what actions can be taken on the transmitted data? Figure illustrates the scenario-alice, the sender, wants to send data to Bob, the receiver. In order to securely exchange data, while meeting therequirements of secrecy, authentication, and message integrity, Alice and Bob will exchange both control message anddata messages. All or some of these messages will typically be encrypted. A passive 96

4 intruder can listen to and record thecontrol and data messages on the channel; an active intruder can remove messages from the channel and/or itself add messages into the channel. different computer usage, the need of computer security nature could be divided into different risk level based on the use, in order to protect the security of computer network and analyse specific security feature based on specific requirements. In practical use, computer confidentiality risk levels are shown in table 1. TABLE 1 : Confidential risk rating scale Fig 1: Message passing between Alice and Bob 5. NATURE OF COMPUTER NETWORK SECURITY Security assessment of computer network security is based on the analysis of users computer network system. Main functions are monitoring whether there are mutations in computer network system and software. It requires a convenient, flexible and complete model to process the analyzation to avoid the complexity of space system. 5.1 Need of security of computer network Classification C1 C2 C3 C4 C5 C6 C7 C8 Feature Description Show host availability. Gets a OS type and version number. Gets the application and version information. Existence of detecting objects in the target host. Read some user specific information. Read more ordinary user files. Read a certain privileged documents or kernel system processes spatial content. Read arbitrary files or system privilege configuration file content monitoring network activity. The need of security of computer network is to fulfil users requirements of computer network s integrity and confidentiality during the usage of computer network. Through a complete systematically security strategy, computer security is insured. The strategy of security of computer network s usage can help computer system to judge users process of usage to prevent unknown attack. It can also insure the system s main movements could reach the requirements of computer network security. With From the table, we can see that every level are rather separated but also connected to each other. Every level could be regarded as a kind of users requirements of computer security. This is the separated part. They do not conflict each other. When unknown personnel attack the computer, after the security feature is destroyed, other risks would appear. Different levels of security vulnerability would influence the occurrence of risks. That s where they are connected. 97

5 5.2 Access permission In the actual use of computer network, system could be set to give different users different levels of access. Foreign counties have analysedthis kind of usage carefully and designed table 3 to limit different users access of the system. Table 2: Access levels Access authority Role description Root The system administrator, equipment management system Super user The user has some special permissions are not ordinary users User Any of a system of ordinary users, with independent private capital resources Guest Anonymous login to access the computer system of the guests Access Remote visitors can access network services, usually trust visitors, can scan the system information 6. TECHNOLOGIES OF COMPUTER NETWORK 6.1 Firewall technology Firewall technology is an array of safety applications to exert mandatory access on external network by using predetermined safety facilities between network systems. Data transfer between two or more networks should follow certain safety measures to monitor the performance, determine whether the communication between the networks is allowed, and monitor the running of the network. 6.2 Data encryption technology Data encryption technology categories can be divided in data storage, data transfer, data integrity, authentication and key management techniques. Data encryption is stored in the memory in order to prevent data loss and destruction. The transmission process in the information encrypted is commonly in the form of circuit encryption and port encryption. Data integrity identification technology is to protect information transfer, storage, access, identification and confidential treatment of people and data. In this process, the system is characterized by the parameter value judgment on whether the input is in line with the set value. Data are subject to validation, and encryption enhanced the protection. Key management is a common encryption in many cases. Key management techniques include key generation, distribution, storage, and destruction, etc. 6.3Intrusion detection technology Intrusion detection technology is to ensure the safety of the design and the rational allocation. Intrusion detection technology can quickly find anomalies in the system and the authorized condition in the report. It can address and resolve system vulnerabilities in a timely manner. Technologies that are not in line with security policies are frequently used. 6.4 Anti-virus technology Anti-virus technology not simply refers to anti-virus software technology. From the effects of its use, it can be classified into network anti-virus software and 98

6 stand-alone anti-virus software. Online anti-virus software focuses on network connection against viruses. Once the virus has invaded the network or diffused to other network data, it will be promptly detected by online virus software, be killed and deleted. 7. TREATS OF COMPUTER NETWORK SECURITY 7.1 Online virus and its features Computer network makes it possible to transfer and exchange information, but also makes computer virus spread and endangers people's safety and privacy. Every day, dozens of virus are found and spread fast, peeking into other s privacy. Survey result of 1500 companies is shown in Table II: Each year, nearly 99 percent of companies have suffered from varying degrees of virus damages. A computer virus is a program capable of autonomous replication with different degree of destruction. Users cannot perceive the replication of these viruses because they hide in the data or frequently used files. Once users use these data or files, the virus will begin replication and spread. This type is called a first-generation computer virus. Now there is a new form of the virus, which is different from the first generation. It doesn t need to hide in the data at all. It hides itself in the network and causes inconvenience to users of malicious code. It takes the advantage of the web media, spreads fast and causes wide range of harm. Table III shows the number of new viruses discovered the domestic antivirus software company in recent years. 7.2 Threats of hackers Besides viruses, there is also a safety hazard, namely, hacker and hacker program. Hacker mainly refers to the illegal invaders to the computer system, who have powerful skills and talents and are obsessed with computers. Hackers may secretly get access to some restricted areas without consent and sneak into other people's computers systems. Currently, hackers are piled in groups, the development trend of which is staggering. Hacker causes great harms, including theft and embezzlement in financial and economic fields. They also spread false advertisings to scam money, steal military, commercial and political secrets, attack other people's copyrights, and manufacture new virus software to spread yellow information. According to the research of FBI, the losses of network security register $ 7.6 billion in USA. The computer network intrusion happens for every 20 minutes. Huge losses are unavoidable. 8. DEFENCE TECHNIQUES FOR COMPUTER NETWORK SECURITY 8.1 Online anti-virus measures According to the characteristics of computer network virus, effective prevention on the virus is difficult and complex. It is a daunting task for network managers to monitor the prevention work. Previous work is only limited to every client computer, in which every user needs to install anti-virus software and on your machine, such as KV300 system, or Rising anti-virus software, etc. However, due to limited computer skill of users, this approach is hard to ensure the safety of the whole network system. As an effective solution to prevent the, the basic requirement is to meet the following demands: 1. Install anti-virus software on computers 2 Update the virus database in users machines 3 Released the latest virus database upgrade file from the WAN connection 4 Coordination and management of remote users virus scanning 5 Address user-reported problems timely 6 Download and preview scan report provided by users 7 Remote control user options 8 Improve the execution speed and zooming ability in large-scale networks People are more capable of preventing online viruses. More anti-virus measures have emerged in order to effectively guarantee the network security. Network management personnel can install 99

7 a complete set of virus software on any client server through one source server. As there are many types of software, network managers should take into account their own situation to achieve the "best use." When choosing solutions, managers should address current situation and leave room for further developments. 8.2 Measure to prevent hackers The invasion and attack can be divided into subjective and objective security issues. Subjectivity security issue mainly refers to errors made by network management personnel. Objectivity security issue mainly refers to loopholes in computers and the network where hackers exploit these vulnerabilities to conduct various forms of attack Use safety tool The above-mentioned basic techniques of computer network security can collect safety issues of host computers. Network management personnel identify these problems in a timely manner and install the patch. Network managers take the advantage of scanning tools (such as NAL's Cyber Cop Scanner) to scan host computers, learn about the weakness links take appropriate preventive and repair measures Firewall technology This paper has described the firewall technology. In short, firewall technology is to prevent others from accessing your network device like a shield. There are three types of firewall technology, namely, packet filtering technology, agent technology, and status monitoring technology. Packet filtering technology is to verify the IP address by setting it. Those IP addresses that do not match those settings will be filtered by the firewall. But this is the first layer of protection. Agent technology is to verify the legitimacy of requests sent by accept client of proxy server to. This technology also involves with user authentication, login, simplified filtering criteria and shielding the internal IP addresses. Status monitoring technology is the third generation of network security technologies, which is effective for all levels of network monitoring. It makes it possible to make timely security decisions. Firewall technology can successfully prevent hacker from intrusion in the local network and protect the network Measures about switch When designing a large-scale regional computer network, we need to ensure that the switch is connected to a network or in a separate network, so that the switch can form a separate management network. This will effectively reduce the number of network switches and narrow the scope of failure. By using search and location, it is also convenient for network managers to quickly handle remote network accidents. 9. Conclusion Computer network security is a complicated issue, involving many aspects of computer technology, network management, network usage and maintenance. In order to increase computer network security, we should mix various types of applications for protection measures. It is necessary to develop more effective security solving measures, thereby to improve the computer network security prevention. REFERENCES [1] AilinZeng, Discission and research on computer network security, Journal of chemical and pharmaceticals (J), [2] International Journal of Advance Foundation and Research in Science & Engineering (IJAFRSE) Volume 1, Issue 3, August [3] Jie Shan, Analysis and research on computer network security, Journal of chemical and pharmaceticals (J),

8 [4] ct-and-full-paper-on-network_13.html. [5] [6] Bart Preneel, Cryptography for Network Security: Failures, Successes and Challenges. [7] Prof. D. Mukhopadhyay, Cryptography and Network Security, Module No. # 01, Lecture No. # 12, Indian Institute of Technology, Kharagpur. 101