Chapter 12 | Computer Virus, Remedy and Protection

 

Write very short answer of the following questions:

a) What type of programs are computer viruses? Useful or harmful?

Ans: Computer viruses are harmful programs.

b) Which type of virus is comparatively not harmful?

Ans: Message carrying virus is comparatively not harmful.

c) Which virus is also known as hybrid virus?

Ans: Multi Paritite Virus is also known as hybrid virus.

d) Do you think antivirus should be installed in your computer?

Ans: Yes, Antivirus should be installed in our computer.

e) Is C-Brain anti virus software?

Ans: No, C-Brain is not anti-virus software.

 

 Write short answer of the following questions:

a) What is computer virus? Write any two examples.

Ans: A computer virus is a software program capable of reproducing itself and capable of causing great harm to files or other programs on the computer system. Some example of computer viruses are: Time Bomb, I Love You, Aids, C-Brain, Logic Bomb etc.

b) Write down any four symptoms of computer virus.

Ans: Some common symptoms of computer virus are:

i) viruses reduce the memory space of computer.

ii) Viruses change the size of computer files.

iii) Viruses change the extension of files.

iv) Viruses show unusual error messages on the computer screen.

v) Viruses may hang or shut down the computer automatically while working.

c) What is antivirus software? Give two examples of antivirus software?

Ans: Antivirus software is a computer program that is used to scan, detect and remove viruses from the computer system. Some examples of antivirus software are Norton antivirus, Anti virus Guard, Kaspersky anti-virus Eset Nod32 Antivirus.

d) How does virus damage our computer?

Ans: Computer viruses cause great harm in the computer system in different ways. It change the extension of files, it change the size of computer files, it hang or shut down the computer automatically etc.

e) Mention the sources of spreading computer virus.

Ans: The most common means of spreading computer viruses are: Internet, Email, Pirated software, USB pen drive, CD/DVD, External Hard drive etc.

 

Write long answer of the following questions:

a) Explain the common types of computer viruses.

Ans: The common types of computer viruses are:

i) Message carrying virus

• ·        Spreads through infected email or chat messages.
• ·        Example: ILOVEYOU Virus - Spread via email with an attachment titled "ILOVEYOU" and infected millions of users.

ii) Boot sector virus

• ·        Infects the boot sector of a storage device, impacting system startup.
• ·        Example: Stoned Virus - One of the earliest boot sector viruses, which displayed a message “Your PC is now stoned” upon infection.

iii) System infector virus

• ·        Targets system files and operating systems, disrupting normal functionality.
• ·        Example: CIH (Chernobyl) Virus - Corrupts system files and overwrites the BIOS, rendering systems unusable.

iv) File infector virus

• ·        Attaches itself to executable files, running when the infected file is opened.
• ·        Example: Cascade Virus - A file infector that caused characters to fall and cascade down the screen.

v) Multi partite virus

• ·        A hybrid virus that spreads through multiple methods, such as both files and boot sectors.
• ·        Example: Tequila Virus - Infects both boot sectors and executable files, spreading through multiple vectors.

vi) Polymorphic virus

• ·        Changes its code or appearance to avoid detection by antivirus software.
• ·        Example: Storm Worm - A polymorphic virus that spread via email and used different signatures to avoid detection.

Each of these virus types has unique methods of infection, and the examples listed demonstrate how these viruses have impacted computers historically.

 

b) "Prevention is better than cure". Justify this statement and mention the preventive measures of your computer from viruses.

Ans: "Prevention is better than cure" emphasizes that it is more effective and less damaging to avoid problems than to fix them once they occur. In the context of computer viruses, taking precautions to protect your system is far easier than dealing with the damage they can cause. To prevent viruses, always use updated antivirus software, avoid downloading attachments or files from un-trusted sources, regularly update your operating system, and use firewalls for additional security. Additionally, backing up important data and avoiding suspicious websites can significantly reduce the risk of infection. Prevention helps maintain system performance and safeguards valuable data from harm.