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Computer Virus (Ch-4) Q/A Solution | 7th Computer | ICSE


Ch-4 (Computer Virus) 

Ex. 1,2 & 3

 

Ex. 4, 5 & 6

Ex. 4 Define

a.      a. Worm: - Worm is a harmless virus that simply replicates itself. But in the long run, it takes over all the resources of the computer system, and eventually the computer becomes useless. Worms have the capacity to travel from system to system very easily.

b.     b. Trojan Horse: - Trojan Horses virus comes as a friendly program (as a game, application, etc.); however, it is very dangerous as it destroys all the data on your system.

c.      c. Rootkit: - Rootkit is a program that hides in a computer and allows someone from a remote location to take full control of the computer.

d.     d. Logic bomb: - A logic bomb is a program, or portion of a program, which lies dormant until a specific piece of program logic is activated. In this way, a logic bomb is very analogous to a real-world land mine. The most common activator for a logic bomb is a date.

e.      e. Adware: - It is a program that displays an unwanted advertisement in a banner, popup window on the web pages, email messages or on other internet services.

f.       f. Spyware: - A program secretly collects the information about the user and then communicates the same information to some outside source while the user is online.

g.     g. Virus signature: - Antivirus programs use virus signature as one of their techniques for detecting viruses. A virus signature also called a virus definition is known specific pattern of virus code.

h.     h. Virus hoax: -Virus Hoax in an e-mail messages that warns user of a non-existent virus or other Malware

Ex. 5

a.     a. What is a computer virus?

Virus stand for Vital Information Resource Under Seize. Viruses are programs which are creative deliberately to damage critical information and data.

b.     b. How does Christmas virus spread?
It is an email worm that spreads via electronic mail as a small, executable file with a variety of names and extensions. The worm is propagated by copying itself onto local and networked drives, as well as emailing itself as an attachment to any addresses.

c.      c. What is a Malware?
Malware (short for malicious software) is a term used for computer viruses, worms, Trojan horses, and rootkits. It is a program that acts without a user’s knowledge and deliberately alters the computer operations.

d.     d. Name some antivirus software programs.

                               i.            Norton Antivirus

                             ii.            Mcafee

                          iii.            Kaspersky Antivirus

                           iv.            panda Antivirus Pro

                             v.            F-Secure Antivirus

                           vi.            AVG Antivirus

                        vii.            TotalLav

                     viii.            Quick Heal

e.      e. Why do we use antivirus program?
An antivirus program protects a computer against virus, identifying and removing any computer virus found in the memory, storage media, or incoming files.

 Ex. 6

a.      a. Explain the different types of viruses.
Type of viruses are following: -
File Infector: This virus can cause irreversible damage to files by permanently destroying the content.
Boot Sector Virus: this virus attaches itself to the boot sector of the disk. This sector is read and loaded into the memory every time the disk is booted. Evidently, this virus is also very dangerous.
Executable File Virus: This virus stores itself in an executable file and infects other files each time the file is run.
Macro Virus: This virus infects files that are created using certain applications or programs that contain macros.

b.     b. What are the source of computer virus?
Email: When you open an e-email attachment that contains a virus, the virus spreads to your computer. If you forward the attachment to other people, their computers will also be affected.
Internet download: There is a lot of stuff to download from the Internet. But if something in the stuff, you want to download, is infected by virus, then the virus comes to your computer system.
Illegal Distribution of Software: If your computer is virus-infected and you copy a software on CD to distribute to someone, the virus of your computer might also get copied on the CD. The person, who installs this software on his computer, unknowingly gets his computer infected by the virus.

c.      c. What are the symptoms of virus?
Symptoms of Viruses are following: -

                               i.            Computer runs much slower than usual.

                             ii.            Memory of computer is less than expected.

                          iii.            Files become corrupted.

                           iv.            Screen displays unusual message or image.

                             v.            Music or unusual sound plays randomly.

                           vi.            Existing programs and files disappear.

                        vii.            Programs or files do not work properly.

                     viii.            System properties change.

d.     d. What are the effects of virus on computer?
    Effects of viruses are following: -

                               i.            It can damage of rename the important files.

                             ii.            It can damage or destroy the operating system.

                          iii.            It can decrease the speed of the computer.

                           iv.            It can reduce the memory or hard disk space.

                             v.            It can infect boot records.

                           vi.            It can infect executable files.

e.      e. What is an e-mail virus? How does it spread?
Email viruses are spread by the files attached to e-mail messages. As e-mail attachments have become more common, the number of e-mail viruses has also increased. You cannot get an e-mail virus from a message that contains only text.
When you open an e-mail attachment that contains a virus, the virus spreads to your computer. If you forward the attachment to other people, their computer will also be affected when they open the attachment.

f.       f. How does Ransomware virus spread?
Ransomware can enter your computer through an email attachment or through your web browser if you happen to visit a website that is infected with this type of virus. It can also access your PC via your network. If your computer has been infected with ransomware, then you most probably won’t be able to access your computer.

g.     g. Write any five precautions that should be taken to prevent computer virus.

                               i.            Do not start a computer with removable media inserted in the drives or plugged in the ports.

                             ii.            Never open an e-mail attachment, unless you are expecting the attachment, and it is from a trusted source.

                          iii.            If a friend unexpectedly sends you a message with an attachment, do not assume that the attachment is safe.

                           iv.            Install an antivirus program on all your computers. Update the software and the virus signature files regularly.

                             v.            Stay informed about new virus alerts and virus hoaxes.

                           vi.            Scan all downloaded programs for viruses and other malware.

            

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