Chapter 12 | Computer Virus, Remedy and Protection ( Updated in 2082)

 

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.

f) What is the full form of VPN?

Ans: The full form of VPN is Virtual Private Network

g) What is the purpose of firewall?

Ans: The purpose of firewall is to protects a computer or network by blocking unauthorized access while allowing safe and authorized communication.

h) Name one popular antivirus software.

Ans: One popular antivirus software is Norton Antivirus.

i) What is malware?

Ans: Malware is the malicious software designed to harm, damage, or gain unauthorized access to a computer system.

j) What is the function of antivirus software?

Ans: Function of antivirus software is to detects, prevents, and removes viruses and other malicious programs from a computer.

 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.

f) list three ways to protect your computer from virus?

Ans: Three ways to protect our computer from viruses:

·        Install and regularly update antivirus software.

·        Avoid downloading files from unknown or untrusted websites.

·        Do not open suspicious email attachments or links.

g. What is the role of antivirus software in your computer security?

Ans: The role of antivirus software in computer security is to scans our computer to detect, block, and remove viruses and other malware and it provides real-time protection and keeps our system safe from harmful threats.

h) What is the importance of keeping software updated?

Ans: The Importance of keeping software updated is to fixes security weaknesses (bugs), improves performance, and protects our computer from newly discovered threats. Updates help keep hackers and malware from exploiting old vulnerabilities.

i) How do viruses spread through email attachments?

Ans: Viruses spread through email attachments because they can be hidden inside infected files. When a user downloads and opens the attachment, the virus activates and infects the computer. It can then spread further by automatically sending infected emails to other contacts.

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.

c) What are the common symptoms of a computer virus infection? How can user protected their system from such infections?

Ans: Common symptoms of a computer virus infection:

• 1.     Slow computer performance.
• 2.     Frequent crashes or freezing.
• 3.     Unwanted pop-up messages.
• 4.     Programs opening or closing automatically.
• 5.     Unknown files or programs appearing.
• 6.     Antivirus software being disabled automatically.
• 7.     Emails being sent from your account without your knowledge.

Ways to protect the system:

• 1.     Install and regularly update antivirus software.
• 2.     Keep the operating system and all software updated.
• 3.     Avoid opening suspicious email attachments or links.
• 4.     Download software only from trusted websites.
• 5.     Use strong passwords and change them regularly.
• 6.     Enable a firewall for network protection.
• 7.     Regularly backup important data.

d) Discuss the role of firewalls and VPNs in enhancing computer security?

Ans: A firewall acts as a security barrier between a computer (or network) and the internet. It monitors incoming and outgoing traffic and blocks unauthorized access while allowing safe communication. Firewalls help prevent hackers, malware, and unauthorized users from accessing private systems.

 A VPN creates a secure and encrypted connection between a user’s device and the internet. It protects sensitive data from hackers, especially when using public Wi-Fi networks. A VPN also hides the user’s IP address, improving privacy and online security.

 Firewalls protect systems by controlling network traffic, while VPNs protect data by encrypting internet connections. Together, they significantly enhance overall computer security.