Chapter :- 10 Computer Virus

February 1, 2023 chinu

Chapter :- 10 Computer Virus

Buzz Words

1. Computer Virus: This is an unwanted malicious program designed to cause damage to computers on a large scale.

2.Security: This is the protection of computer systems from the theft or damage to the hardware,software or the information on them.

3.Malware: This is an abbreviated term for “malicious software”. This is specifically designed to gain access

or damage a computer without the knowledge of the owner.

4. Trojan horse: A threat to computer security that does not replicate itself but they can be destructive.

5. Worms: It uses up the computer hard disk space by replicating itself and or slow down the data transmission on the internet.

6. Spyware: This tracks the daily activity of the computer so that the attacker can make use of our information.

7. Boot Sector Virus: It effects the booting sector of the computer.

8. File Deleting Virus: This is designed to delete important files which are the part of Operating System or data files,

9. Macro Virus: This virus specifically infect data files like documents, spread sheets, presentations, etc.

10. Polymorphic Viruses: These have the capability to change their appearance and alter their code every time they infect a different system.

11.Multipartite Virus: This is designed to infect both the boot sector and files on our computer.

12. Antivirus Software: This is a program that detects, prevents, and removes viruses from a computer.

13. Quarantined Files: These are those files which are suspected to be infected and might be a threat to the system

Fill in the blanks

1. Malware is an abbreviated term for “malicious software?

2. Computer Security is the protection of computer systems from the theft or damage to the hardware or software of the computer.

3. Polymorphic viruses have the capability to change their appearance.

4. An Antivirus software is a program that detects, prevents, and removes viruses from a computer.

5. Spyware is designed to spy on the victim’s computer

6. The Boot Sector is also known as the Master Boot Record

7. Window Defender is the built in antivirus of Microsoft windows.

State whether True or False

1. A multipartite virus is designed to infect both the boot sector and files on our computer. True

2. A virus cannot spread through Flash drives. False

3.Antivirus software cannot delete infected files False

4. If we are unable to open any file on the computer, there is a possibility that the computer might be infected by a virus. True

5. An email can never contain an infected file attachment. False

6.The Antivirus software must be upgraded regularly True

Multiple Choice Questions.

1. If a computer is infected by virus, it will show the following symptoms

(i) New programs are not able to be installed.
(ii)Computer may take long time to start.
(iii) Unable to open files or folders.
(iv) All of the above.

2. A computer virus does not spread by

(i) email attachments.
(ii) opening authentic websites
(iii)from other computers
(iv) infected Flash drives

3. We should protect our computer by

(i) opening all email attachments
(ii)using an antivirus software
(iii) washing the computer regularly
(iv) using infected Flash drives

4.The primary functions of Antivirus software are

(i) Virus detection
(ii)System analysis
(iii)Online protection
(iv) All of the above

5. Which of the following is not a threat to computer security ?
(i)Worms
(ii)Trojan Horse
(iii)Spyware
(iv)Antivirus software

Match the following

Answer briefly

1. Define computer virus.
Ans :- A computer virus is an unwanted malicious program designed to cause damage to computers on a large scale.

2.Mention any two harmful effects of virus on the computer.
Ans :- 1. There is a decrease in the speed of the computer.
2. There is unexplained crashing of the hard disk.

3. What is activation of virus?
Ans :- When the computer virus starts working, it is called the activation of virus.

4. Name the threats to computer security.
Ans :- Malware: Trojan ,worms and spyware

5.How does the virus spread through emails?
Ans :- An email may contain an infected fi le attachment. Virus can spread if the user opens and downloads an infected email attachment

6. Why should the Antivirus software be updated regularly?
Ans :- When the Antivirus program is updated, its database of the existing virus is updated with the code and the name of the new viruses. This helps the Antivirus software to be up-to-date and keeps our computer safe and protected from any malicious software.

7. What are Quarantined files?
Ans :- Quarantined Files are those fi les which are suspected to be infected and might be a threat to the system

Answer the following.

1. How is Trojan, Spyware and Worms different from each other?
Ans :-
Trojan makes changes to the computer settings.
Worms: It uses up our computer hard disk space by replicating itself and or slows down the data transmission on the internet due to consumption of the bandwidth.
Spyware: It tracks our activity on the Internet and transmits that information in the background to someone else.

2. Describe the ways a computer virus spreads.
Ans :- A computer virus spreads through:
1. Infected Flash Drives or Disks: A virus can also be copied from one computer to other when the user copies infected fi les using fl ash drives.
2. Email Attachments: An email may contain an infected fi le attachment. Virus can spread if the user opens and downloads an infected email attachment.
3. Networks: Virus can spread to other computers if an infected computer is connected to a network

3. Explain the different types of computer virus.
Ans :-
1. Boot Sector Virus: The Boot Sector is a part of our computer that gets accessed fi rst when we switch it on.
2. File Deleting Virus: A File Deleting Virus is designed to delete important fi les which are the part of Operating System or data fi les.
3. Macro virus: Macro viruses are written by using the Macro programming languages to specifi cally infect data fi les like documents, spread sheets, presentations, etc.
4. Polymorphic Virus: Polymorphic Viruses have the capability to change their appearance and alter their codes, every time they infect a different system.
5. Multipartite Virus: A multipartite virus is designed to infect both the boot sector and fi les on our computer

4. How can we protect our computer? List any four ways.
Ans :-
1. The latest and updated version of antivirus and fi rewall should be installed on the computer.
2. The antivirus software must be upgraded regulaarly.
3. Flash drives(Pen drives) should be scanned for viruses, and should not be used on infected computers.
4. Junk or unknown emails should not be opened and must be deleted immediately

5. What are the functions of Antivirus software?
Ans :-
1. Virus Detection: The primary function of antivirus software is to detect and remove computer viruses.
2. System Analysis-Antivirus programs also monitor our computer to check if the system components are functioning correctly.
3. Online Protection-Antivirus software monitors the websites visited by the web browser of our computer