BCA_Sem IV_Computer Networks_Second Draft

standalone malware computer program that replicates itself in order to spread to other computers. It often uses a computer network to spread itself, relying on security failures on the target computer to access it. It will use this machine as a host to scan and infect other computers.  A worm is similar to a virus because they both are self‐replicating, but the worm does not require a file to allow it to propagate. There are two main types of worms, mass‐mailing worms and network aware worms. Mass mailing worms use email as a means to infect other computers. Network‐aware worms are a major problem for the Internet. A network‐aware worm selects a target and once the worm accesses the target host, it can infect it by means of a Trojan or otherwise.  Trojans appear to be benign programs to the user, but will actually have some malicious purpose. Trojans usually carry some payload such as a virus.It is a type of malware. It is often distinguished as legitimate software. They can be employed by cyber thieves and hackers trying to gain access to users systems. In computing, a Trojan horse is any malware which misleads users of its true intent. The term is derived from the Ancient Greek story of the deceptive Trojan Horse that led to the fall of the city of Troy.  Phishing is an attempt to obtain confidential information from an individual, group, or Organization. Phishers trick users into disclosing. It is a type of social engineering attack often used to steal user data including login credentials and credit card numbers. Phishing is a type of social engineering where an attacker sends a fraudulent message designed to trick a human victim into revealing sensitive information to the attacker or to deploy malicious software on the victim's infrastructure like ransom ware.  Data security is the aspect of security that allows a client’s data to be transformed into unintelligible data for transmission. Even if this unintelligible data is intercepted, a key is needed to decode the message. This method of security is effective to a certain degree. Strong cryptography in the past can be easily broken today. Cryptographic methods have to continue to advance due to the advancement of the hackers as well.  When transferring cipher text over a network, it is helpful to have a secure network. This will allow for the cipher text to be protected, so that it is less likely for many people to even attempt to break the code. A secure network will also prevent someone from inserting unauthorized messages into the network. Therefore, hard ciphers are needed as well as attack‐hard networks. 15.5 KEYWORDS  Network Security – It is a broad term that covers a multitude of technologies, devices and processes. Network security consists of the policies, processes and 251 CU IDOL SELF LEARNING MATERIAL (SLM)

practices adopted to prevent, detect and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources.  Virus – It is a type of malicious code or program written to alter the way a computer operates and is designed to spread from one computer to another. In more technical terms, a computer virus is a type of malicious code or program written to alter the way a computer operates and is designed to spread from one computer to another. A virus operates by inserting or attaching itself to a legitimate program or document that supports macros in order to execute its code.  Worm- A computer worm is a standalone malware computer program that replicates itself in order to spread to another computer. A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers. It often uses a computer network to spread itself, relying on security failures on the target computer to access it. It will use this machine as a host to scan and infect other computers.  Phishing – It is a type of social engineering attack often used to steal user data including login credentials and credit card numbers. Phishing is a type of social engineering where an attacker sends a fraudulent message designed to trick a human victim into revealing sensitive information to the attacker or to deploy malicious software on the victim's infrastructure like ransom ware.  Trojan – It is a type of malware. It is often distinguished as legitimate software. They can be employed by cyber thieves and hackers trying to gain access to users systems. In computing, a Trojan horse is any malware which misleads users of its true intent. The term is derived from the Ancient Greek story of the deceptive Trojan Horse that led to the fall of the city of Troy. 15.6 LEARNING ACTIVITY 1. Discuss the network security checks one will ensure while installing in an IT company. ___________________________________________________________________________ ___________________________________________________________________________ 2. Discuss the various network frauds happened in Internet. ___________________________________________________________________________ ___________________________________________________________________________ 15.7 UNIT END QUESTIONS A.Descriptive Questions 252 CU IDOL SELF LEARNING MATERIAL (SLM)

Short Questions: 1. List the reasons for the introduction of network intrusions. 2. Explain worms. 3. Define Trojans. 4. Define phishing. 5. Define virus attack in computer network. Long Questions: 1. Explain the different attacking methods in network. 2. What are the things to be considered while developing a secure network? 3. Explain network security. 4. Describe security timelines. 5. What is importance of data security? B. Multiple Choice Questions 1. Identify the layer from which the physical layer translates logical communications requestedinto hardware specific operations? a. Data link layer b. Network layer c. Transport layer d. Application layer 2. Which is not a function of network layer? a. Routing b. Internetworking c. Congestion control d. Error control 3. What is the name of the field that covers a variety of computer networks, both private and public that is used in every day jobs? a. AI b. ML c. Network security d. IT 253 CU IDOL SELF LEARNING MATERIAL (SLM)

4. Which is not an objective of network security? a. Identification b. Authentication c. Access control d. Lock 5. What is termed for the process of verifying the identity of a user? a. Authentication b. Identification c. Validation d. Verification Answers 1-a, 2-d, 3-c, 4-d, 5-a 15.8 REFERENCES References  W, Stallings. (n.d). Data and Computer Communications. Eight Editions. Pearson Education.  Stamper, D. (1993). Local Area Networks, Addison-Wesley, Reading. MA.  Stamper, D. (1991). Business Data Communications, Third Edition. Addison-Wesley, Reading, MA. Textbooks  Behrouz, A, Forouzan. (n.d). Data communications and Networking. Fourth Edition. Mc-Graw Hill Achyut Godbole, ―Data communications and Networks, TMH.  Dr. Sidnie, Feit. (n.d). TCP/IP. Second Edition. TMH  Computer Networks – Andrew Tannenbaum. Websites  http://www.garymgordon.com/misc/tutorials/networking/Lesson2.pdf  http://networkworld.com/ns/books/ciscopress/samples/0735700745.pdf  http://pages.cs.wisc.edu/~tvrdik/7/html/Section7.html  http://fcit.usf.edu/network/chap2/chap2.htm 254 CU IDOL SELF LEARNING MATERIAL (SLM)