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 deliberate damage,leaks or changes. Generally speaking, network security is inextricably related to the confidentiality integrity,authenticity and reliability of network. Its control technologies and concepts are necessary to analyze.
Computer technology is more and more ubiquitous; the penetration of computer in society is a welcome step towards modernization but society needs to be better equipped to grapple with challenge associated with technology. New hacking technique are used to penetrate in the network and the security vulnerabilities which are not often discovered create difficulty for the security professionals in order to catch hackers. The difficulties of staying up to date with security issues within the realm of IT education are due to the lack of current information. The recent research is focused on bringing quality security training combined with rapidly changing technology. Online networking security is to provide a solid understanding of the main issues related to security in modern networked computer systems. This covers underlying concepts and foundations of computer security, basic knowledge about security-relevant decisions in designing IT infrastructures, techniques to secure complex systems and practical skills in managing a range of systems, from personal laptop to large scale infrastructures. The security of network is a big issue for security administrators because network is growing day by day. Security on the Internet and on Local Area Networks is now at the forefront of computer network related issues . Network security consists of the provisions and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources. Network security involves the authorization of access to data in a network, which is controlled by the network administrator .Each and every client who is working on the internet wants security of information but sometimes he or she do not know that someone else may be a intruder is collecting the information. Information is an asset that must be protected . Network security is the process by which digital information assets are protected, the goals of security are to protect confidentiality, maintain integrity, and assure availability. To secure the information and the entire network system, one specific methodology is required which can be capable of providing the complete security solutions.
# TYPES OF NETWORK THREATS
A computer worm is standalone malware computer program that replicates itself in order to spread to other computers.
Often, it uses a computer network to spread itself, relying on security failures on the target computer to access it.
Unlike a computer virus, it does not need to attach itself to an existing program.
Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.
Users can minimize the threat posed by worms by keeping their computers' operating system and other software up-to-date, avoiding opening unrecognized or unexpected emails, and running firewall and antivirus software.
A computer virus attaches itself to a program or file enabling it to spread from one computer to another, leaving infections as it travels.
Almost all viruses are attached to an executable file, which means the virus may exist on your computer but it actually cannot infect your computer unless you run or open the malicious program.
It is important to note that a virus cannot be spread without a human action, (such as running an infected program) to keep it going.
Because a virus is spread by human action people will unknowingly continue the spread of a computer virus by sharing infecting files or sending emails with viruses as attachments in the email.
The Trojan Horse, at first glance will appear to be useful software but will actually do damage once installed or run on your computer.
Those on the receiving end of a Trojan Horse are usually tricked into opening them because they appear to be receiving legitimate software or files from a legitimate source.
When a Trojan is activated on your computer, the results can vary. Some Trojans are designed to be more annoying than malicious (like changing your desktop, adding silly active desktop icons) or they can cause serious damage by deleting files and destroying information on your system.
Trojans are also known to create a backdoor on your computer that gives malicious users access to your system, possibly allowing confidential or personal information to be compromised. Unlike viruses and worms, Trojans do not reproduce by infecting other files nor do they self-replicate.
Spam is one of the more common methods of both sending information out and collecting it from unsuspecting people.
It refers to the mass distribution of unsolicited messages or advertising to addresses which can be easily found on the Internet through things like social networking sites, company websites and personal blogs.
A spam can annoy you with unwanted junk mail.
Create a burden for communications service providers and businesses to filter electronic messages.
Phish for your information by tricking you into following links or entering details with too-good-to-be-true offers and promotions.
Provide a vehicle for malware, scams, fraud and threats to your privacy.
Adware, or advertising-supported software, is any software package that automatically renders advertisements in order to generate revenue for its author. The advertisements may be in the user interface of the software or on a screen presented to the user during the installation process.
The functions may be designed to analyze which Internet sites the user visits and to present advertising pertinent to the types of goods or services featured there.
The term is sometimes used to refer to software that displays unwanted advertisements known as malware .The authors of these applications include additional code that delivers the ads, which can be viewed through pop-up windows or through a bar that appears on a computer screen
Spyware is software that aims to gather information about a person or organization without their knowledge and that may send such information to another entity without the consumer's consent, or that asserts control over a computer without the consumer's knowledge. Spyware applications are typically bundled as hidden component of freeware or shareware programs that can be downloaded from the Internet; however, it should be noted that the majority of shareware and freeware applications do not come with spyware.
Once installed, the spyware monitors user activity on the Internet and transmits that information in the background to someone else.
Spyware can also gather information about e-mail addresses and even passwords and credit card numbers.
A technique used to gain unauthorized access to computers, whereby the intruder sends messages to a computer with an IP address indicating that the message is coming from a trusted host. (source address is forged).To engage in IP spoofing, a hacker must first use a variety of techniques to find an IP address of a trusted host and then modify the packet headers so that it appears that the packets are coming from that host. Newer routers and firewall arrangements can offer protection against IP spoofing.
A Zombie Drone is defined as a hi-jacked computer that is being used anonymously as a soldier or ‘drone’ for malicious activity (e.g., distribute unwanted spam e-mails) by an unknown party.
These unknown individuals, also called spammers, search for un-patched computers connected to the Internet with the intent of identifying machines that are vulnerable to attack.
Once a computer system is hi-jacked, spyware can be downloaded to the vulnerable computer without the user’s knowledge. Spyware can be used for many malicious activities such as routing thousands of unwanted e-mails from your address to unknown recipients. It can even record your keystrokes, which could lead to the compromise of your personal information.
BASIC NETWORK TECHNOLOGIES
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.
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.
INTRUSION 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.
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 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.
MEASURES TO IMPROVE NETWORK SECURITY
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 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.
MEASURES 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
2.1 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.
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 an location, it is also convenient for network managers to quickly handle remote network accidents.
There are threats that can attack the resources (information or devices to manage it) exploiting one or more vulnerabilities. The resources can be protected by one or more countermeasures or security controls. So, security services implement part of the countermeasures, trying to achieve the security requirements of an organization
Confidentiality refers to preventing the disclosure of information to unauthorized individuals or systems. For example, a card transaction
on the Internet requires the credit card number to be transmitted from the buyer to the merchant and from the merchant to a transaction network. The
system attempts to enforce confidentiality by encrypting the card number during transmission, by
limiting the places where it might appear (in databases, log files, backups, printed receipts, and
so on), and by restricting access to the places where it is stored. If an unauthorized party obtains the card number in any way, a breach of confidentiality has occurred.
In information security, data integrity means maintaining and assuring the accuracy and
consistency of data over its entire life-cycle.
This means that data cannot be modified in an unauthorized or undetected manner. Integrity is violated when a message is actively modified intransit. Information security systems typically provide message integrity in addition to data confidentiality
For any information system to serve its purpose, the information must be available when it is needed. This means that the computing systems used to store and process the information,the security controls used to protect it, and the communication channels used to access it must be functioning correctly.
High availability systems aim to remain available at all times, preventing service disruptions due to power outages, hardware failures, and system upgrades. Ensuring availability also involves preventing denial-of-service attacks.
In computing,e-Business, and information security, it is necessary to ensure that the data,transactions, communications or documents (electronic or physical) are genuine. It is also important for authenticity to validate that both parties involved are who they claim to be. Some information security systems incorporate authentication features such as "digital signatures",which give evidence that the message data is genuine and was sent by someone
possessing the proper signing key.
In law,non-repudiation implies one's intention to fulfill their obligations to a contract. It also implies that one party of a transaction cannot deny having received a transaction nor can the other party deny having sent a transaction.
It is important to note that while technology such as cryptographic systems can assist in non-repudiation efforts, the concept is at its core a legal concept transcending the realm of technology. It is not, for instance, sufficient to show that the message matches a digital signature signed with the sender's private key, and thus only the sender could have sent the message and nobody else could have altered it in transit. The alleged sender could in return demonstrate that the digital signature algorithm is vulnerable or flawed, or allege or prove that his signing key has been compromised. The fault for these violations may or may not lie with the sender himself, and such assertions may or may not relieve the sender of liability, but the assertion would invalidate the claim that the signature necessarily proves authenticity and integrity and thus prevents repudiation.
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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 and. It is a long way to go to ensure the normal operation of large-scale network system and communication and maintain sustainable and efficient transport network. To build a harmonious secure computer network security system, we need to take advantage of a variety of integrated network security and green data networking products to form an intelligent network protection system and thus make computer network security meets
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