8th COMPUTER SECURITY THREATS UNIT-02

Q1. Tick the correct choice for the following questions.

i. Which of the following is a malicious program that replicates and spreads independently and harms the computer?

a. Virus

b. Worm (Correct Answer)

c. Adware

d. Spyware

ii. Which malicious program records user’s behavior on the Internet, display ads and can even download other malicious software on the computer?

a. Virus

b. Spyware

c. Adware (Correct Answer)

d. Worm

iii. A website that is set up to spread a virus or for some other unethical purpose is called an ____________________________.

a. Secure Website

b. Non-informative website

c. Informative website

d. Insecure website (Correct Answer)

iv. Which of the following is a computer program that detects, prevents, and takes action to deactivate or remove malicious program?

a. Virus Program

b. Operating System

c. Antivirus Program (Correct Answer)

d. Word Processor

v. ____________________________ contains the information about malware which can be used to identify them.

a. Virus Definition file (Correct Answer)

b. Word file

c. Excel file

d. E-mail attachment

vi. Which of the following is a common source of spreading viruses in computer?

a. Infected flash drives or disks (Correct Answer)

b. E-mail attachments

c. Surfing insecure websites

d. Installing Pirated Software

vii. ____________________________ is the unauthorized use of computer, network and its resources.

a. Programming

b. Hacking (Correct Answer)

c. Stealing

d. Robbing

Q2. Fill in the blanks.

i. An e-mail virus is a computer code sent as ____________________________ to other computers.

Answer: e-mail attachment

ii. People who indulge themselves in hacking activities are called ____________________________.

Answer: hackers

iii. Some common types of ____________________________ to the computers are Virus, Worms, Hackers and Adware.

Answer: threats

iv. Software which has been duplicated and distributed without authorization is called ____________________________ software.

Answer: Pirated

v. ____________________________ is software which automatically plays, displays, or downloads advertisements to a computer, usually without user’s knowledge.

Answer: Adware

Q3. Match Column A with Column B.

Q4. Give brief answers to the following questions.

i. List some effects / indicators of security threats.

Answer: Effects/Indicators of security threats

The computer runs slower than usual.
The computer locks up or stops responding.
The computer suddenly restarts on its own.
Frequently used programs become suddenly slow to load and operate.
Applications and disk drives are suddenly inaccessible.
Unusual error messages appear.
Unexpected icons appear on the desktop
Antivirus software is disables or does not run.

ii. Differentiate between a virus and a worm.

Answer: Difference between a virus and a worm

A computer virus is a program written intentionally to alter the way a computer operates, without the permission or knowledge of the user, while computer worms are malicious programs that replicate and spread independently without user action and harm the computer. Worms spread through network and over the internet to computers that are connected to the internet.

A virus replicates and executes itself by attaching copies to other files such as program files or documents so that the user chicks them and the virus activates, while worms can spread by copying themselves from disk to disk or by e-mail.

iii. How viruses and worms spread through e-mail attachments?

Answer: Virus and Worms spread through e-mail attachments

An E-mail attachment is a file that can be sent with an e-mail from one computer to the other. An e-mail virus is a computer code sent as an e-mail attachment. If activated, it may cause some harmful effect, such as destroying certain files on the hard disk and causing the attachment to be forwarded to everyone in the address book. E-mail viruses distribute themselves automatically by e-mail.

These require the user to double-click on the attachment containing the virus. This cause the malicious code to mail itself to other people from that computer.

vi. Who is a hacker? What can a hacker do?

Answer: Hacker

People who indulge themselves in computer hacking activities are called hackers. Hackers are computer experts who use their expertise for malicious purposes.

Hacker can steal

Client or customer information
Credit card details and social security numbers, for identity fraud or theft
Passwords
Email addresses, which may be used for spamming

v. How Adware affect the working of a computer?

Answer: Adware

Adware is a software which automatically plays, displays, or downloads advertisements to a computer usually without user’s knowledge. These advertisements can be in the form of a pop-up. They record user’s behavior on the Internet, display ads and can even download other malicious software on to the computer.

vi. Name the different types of viruses.

Answer: Different types of viruses

Virus
Adware
Hackers
Worms

vii. What is Antivirus?

Answer: Antivirus

Antivirus software is a computer program that detects, prevents, and takes an action to deactivate or remove malicious programs (Viruses, Worms, and Adware etc.).

An antivirus program runs in the background all the time and informs the user when some malware is detected.

An antivirus software protects a computer connected to the network computers. For all computer users, it is very important to have a proper antivirus program installed in their computer to secure data and programs.

Q5. Give detailed answers to the following questions.

i. Explain different threats to the security of a computer.

Answer: Different threats to the security of a computer

Computer systems are vulnerable to many threats ranging from errors, harming stored data, information or corrupting programs installed on the computers. The following are some common types of threats to computers:

Virus
Worms
Hackers
Adware

Virus:

Computer virus is the most common and well-known computer security threat. A computer virus is a program written intentionally to alter the way a computer operates, without the permission or knowledge of the user. A virus replicates and executes itself by attaching copies to other files such as program files or documents so that the user chicks them and the virus activates.

When activated, a virus may:

Damage or delete files
Erase data from hard disk
Cause erratic system behavior
Display annoying messages, etc.

Example of viruses are: NYB, AntiExe, Casecade, FRODO, Win95 and ZmistA etc.

Worms:

Computer worms are malicious programs that replicates and spread independently without user action and harm the computer. Worms spread through network and over the internet to computers that are connected to the Internet. Worms can also be spread by copying themselves from disk to disk or by e-mail. SQL Slammer, The Blaster Worm, Sasser worms, Mellissa and ILOVEYOU are some examples of computer worms.

Computer worms can:

Destroy files in the system.
Slow down the computer.
Cause some programs to stop working.

Adware:

Adware is a software which automatically plays, displays, or downloads advertisements to a computer, usually without user’s knowledge. These advertisements can be in the form of a pop-up. They record user’s behavior on the Internet, display ads and can even download other malicious software on to the computer.

They may also be in the user interface of the software or on a screen presented to the user during the installation process.

Hackers:

Hacking can be defined as the unauthorized use of computer, network and its resources. People who indulge themselves in computer hacking activities are called Hackers. Hackers are computer experts who use their expertise for malicious purposes.

Hackers Steals:

Client or customer information
Credit card details and social security numbers, for identity fraud or theft
Passwords
E-mail addresses, which may be used for spamming.

ii. Explain various ways through which security threats spread in computers.

Answer: Various ways through which security threats spread in computers

There are different ways through which a Virus, Worms and Adware spread from one computer to the other computer. A Virus, Worms and Adware can spread through:

Infected Flash Drives or Disks
E-mail attachments
Surfing insecure websites
Installing Pirated Software

Infected Flash Drives or Disks:

Flash drives and disks are convenient, popular and easy to use storage devices. Flash drives and disks are the main source of spreading viruses among computers. Once an infected flash drive or a disk is connected to a healthy computer, it becomes infected with viruses. In this way, virus spread from one computer to the other.

E-mail Attachments:

These require the user to double-click on the attachment containing the virus. This cause the malicious code to mail itself to other people from that computer.

The best defense against e-mail viruses is to never open an unknown e-mail.

Surfing Insecure Websites:

A Website that is set up to spread a virus or for some other unethical purpose is an insecure website. These websites engage in questionable or unethical practices and attempt to:

Automatically access the computer when user visit them.
Install Adware that may cause a flurry of pop-ups to appear on the screen.

Installing Pirated Software:

Software which has been duplicated and distributed without authorization is called Pirated Software. Pirated software may be faulty or loaded with malware and may contain viruses.

Pirated software can threaten the safety of computer users. These software products may be used to steal personal information, load a computer with viruses, or engage in activities which can harm the computer.

iii. Give the steps to update the virus definition of antivirus software.

Answer: Steps to update the virus definition of antivirus software.

Virus Definitions contains the information about malware which can be used to identify security threats. They are very important while scanning a computer. Virus Definitions tell the antivirus software to recognize viruses. When antivirus software installed, a file containing a set of virus definition file is also installed. To protect the computer from the most current viruses, user must update the antivirus software regularly. Most of the antivirus programs have auto update feature that enables the antivirus program to download profiles of new viruses so that it can check for the new viruses as soon as they discovered.

An Antivirus Update is an up gradation of already installed software. Update virus definitions can protect and clean the computer from the most recent computer viruses and other security threats.

iv. What is meant to be scanning computer, and what are the steps to scan a computer?

Answer: Scanning a Computer

Scanning the computer for threats like viruses, worms, adware, etc. is very important to keep a computer system in good working condition. It helps to protect a computer from different computer security threats.

To scan a computer, user needs to install antivirus software on the computer to perform this significant task. The antivirus software enables the user to detect and remove computer viruses and also repair infected files if possible.

Steps to scan computer using AVG Antivirus

Follow these steps to scan the computer using AVG antivirus software:

Click start=> Programs=>AVG Free Edition=>AVG Antivirus Free Edition for Windows
Click “Update Manager” for updates and check for updates before scanning computer.
Click “Scan now”. It will start scanning the computer for infected files. This will take some time to scan the computer.
The “whole computer scan” option can be launched directly from the scanning interface by clicking on it.
If viruses are detected, they will be automatically removed or sent to the “Virus Vault”.

v. What is meant by virus definitions / updates? Why they are important? Explain.

Answer: Virus Definitions

Virus Definitions contain the information about malware which can be used to identify security threats. While scanning a computer, Virus Definitions tell the antivirus software to recognize viruses. When antivirus software is installed, a file containing a set of virus definitions file is also installed.

To protect the computer from the most recent viruses, the user must update antivirus software regularly. Most antivirus programs include an auto-update features that enables the antivirus program to download profiles of new viruses so that it can check for the new viruses as soon as they are discovered.

An Antivirus Update is an up-gradation of already installed antivirus software. Update virus definitions can protect and clean the computer from the most recent computer viruses and other security threats.

10th Class Computer New Course User Interaction Unit-02 Q.1 Multiple choice questions. printf is used to print ____________________ type of data. a) int b) float c) char d) All of them (Correct Answer) 2. scanf is a ____________________ in C programming language. a) keyword b) library c) function (Correct Answer) d) none of them 3. […]

10th Class Computer New Course ITP Unit-01

In this unit, we will learn programming environment, tools for writing programs, who and how to write the computer program and how we get the require result.

9th Computer New Course Designing Website Unit-05

In this unit, we will learn HTML basics, text formatting, creating lists, images, background, hyperlinks, and creating tables. Then we will solve the exercise.

9th Computer New Course Data and Privacy Unit-04

"Secure data transfer". Data is converted to unreadable format before sending and then converted to readable format after reaching it's destination.

9th Computer New Course Networks Unit-03

9th Computer New Course Networks Unit-03 3.1 Choose the correct option. The IPv4 address is made up of ____________________ binary bits. i. 31 ii. 29 iii. 32 (Correct Answer) iv. 30 2. Routing is the process of taking data from one device and sending it to another device in different ____________________. i. Channel ii. Network […]

9th Computer New Course Binary System Unit-02

A computer understands the language of 1s and 0s only, called machine language. The number system that only contains 1s and 0s is called binary number system.