Computer viruses, worms, Trojan horses, spyware, and other malware can harm computer systems in various ways. Anti-virus software, firewalls, and other security measures help protect against malware threats. Digital certificates, digital signatures, strong passwords also help secure computer systems and networks from unauthorized access.

1. PREVIOUS YEARS QUESTIONS WITH
ANSWER AND EXPLANATION
Part - 5
vrrgroup.academy@gmail.com
https://www.facebook.com/VRRAcademy
www.youtube/VRR Academy
1

2. 2
VIRUS: Vital Information Resource Under Siege.
• Computer virus is a small software program that spreads
from one computer to another and that interferes with
computer operation.
• A piece of software that infects programs
• modifies them to include a copy of the virus
• replicates and goes on to infect other content
• easily spread through network environments

3. 1. Boot sector infector: Infects a master boot record or boot
record and spreads when a system is booted from the disk
containing the virus (poly boot.B, anti EXE etc.)
2. File infector: Infects files that the operating system considers
to be executable (*.exe, *.com)
3. Macro virus: It infects files that are created using certain
applications or programs that contain macros like .doc, .xls .ppts
etc. (Ex: Melissa)
4. Multipartite virus: Infects files in multiple ways (Ex: Flip)
5. Encrypted virus: A portion of the virus creates a random
encryption key and encrypts the remainder of the virus. 3

4. 4
6. Stealth virus: A form of virus explicitly designed to hide itself
from detection by anti-virus software
7. Polymorphic virus: A virus that mutates with every infection /
goes on to create a large number of copies (Ex: Elkern, Tuareg)
8. Metamorphic virus: A virus that mutates and rewrites itself
completely at each iteration and may change behavior as well
as appearance.
9. Web scripting virus: Many websites execute Complex code in
order to provide interesting content. These websites are
sometimes created with purposely infected code. (Ex: JS.
Fortnight)
10. FAT virus: It is used to store all the information about the
location of files, unusable space etc. (Ex: Link virus)

5. 11. File system virus: It is also called cluster virus or directory virus. It
infects the directory of your computer by changing the path that
indicates the location of a file. (Ex: Dir-2 virus)
12. Overwrite virus : It deletes the information contained in the files
that it infects, rendering them partially or totally useless, once they
have been infected. (Ex: Way, Trj.Reboot, Trivial.88-D etc.)
13. Direct action virus: It comes into action when the files containing
the virus is executed. it infects files in the folder that are specified in
the AUTOEXEC.BAT file path. (Eg. vienna virus)
14. Resident virus : It's fixes themselves into the systems memory and
get activated whenever the operating system runs and infects all the
files that are then opened. It hides in the RAM memory and stays there
even after the malicious code is executed. (E.g., Randex, Meve etc.)
5

6.  It is a computer program that replicates itself in order to spread to
other computers.
 Worms almost always cause atleast some harm to the network,
even if only by consuming bandwidth, where as virus almost
always corrupt or modify files on a targeted computer.
 worms are hard to detect because they are invisible files.
 Eg: Bagle, I love you, Morris etc.
 e-mail worms spread in macro or script code included in
attachments and instant messenger file transfers
6

7.  It is a non- self- replicating type of Malware which appears to perform
a desirable function but instead facilitates unauthorised access to the
users computer system.
 Trojans do not attempt to inject themselves into other files like a
computer virus.
 Trojan Horses may Steal information, or harm their host computer
systems.
 Trojan Horse install via online games or internet driven application in
order to reach the target computers.
 It is non-replicating in nature.
 e.g., beast, zeroAccess Rootkit etc.
7

8. The sources of virus could be:
1. Downloadable programs
2. Cracked software
3. Internet
4. Email attachments
5. Booting from unknown CD / USB Drive
8

9. EFFECTS OF VIRUS
Depending on the types of virus their effects on the computer are:-
 Destroy all data on your local disk.
 Slow down your computer performance.
 Monitor what are you doing.
 Download illegal files onto your computer without being able to delete
them.
 Generates IP address randomly and sends those IP address automatically.
 Steal confidential information like password, account number, credit card
information by random e-mailing.
 May increase or decrease memory size.
 Display different types of error messages.
 Alter PC settings.
 Cause computer to make strange noises make music, clicking noises or
beeps.
9

10.  Spyware is program which is installed on a computer system to spy on
the system owner's activity and collects all the information which is
misused afterwards.
 Spyware can transmit personal information to another person's
computer over the internet.
Spyware can harm in many ways like:-
1. Steal your password.
2. Observe your browsing choices.
3. Redirect your web browser to phishing pages.
4. Can alter your computer settings ( web browser, home page settings or
placement of your desktop icon).
e.g., cool web search, FinFisher,
10

11. SPOOFING
 Spoofing is a technique to access the unauthorised data
without concerning to the authorised user over the network.
11
HACKING
• It is Act of intruding into someone else's computer or network.
• It prevents the authorised users from accessing the resources of the
computer.
• Taking administrative privileges.

12. PHISHING
 It is an attempt to fraudulently acquire sensitive information such as
passwords, credit cards details, etc by masquerading as a
trustworthy person.
 It is an act of sending unsolicited bulk messages in the form of
emails.
 It is a subset of electronic spam involving nearly identical messages
sent to numerous recipient by emails.
 It is a type of internet fraud that seeks to acquire a user's credential
by deception.
12

13.  It is an act of sending unsolicited bulk messages in the form of
emails.
 It is a subset of electronic spam involving nearly identical
messages sent to numerous recipient by emails.
13

14. ROOTKITS
 Rootkit is a set of software tools that enables an unauthorized
user to gain control of a computer system without being
detected.
 Rootkits can change how the operating system functions.
 Rootkits are also difficult to remove, in some cases, require a
complete re-installation of the operating system.
14

15. LOGIC BOMB
 It is a malicious program intentionally inserted into software system and is
timed to cause harm at certain Point in time but is inactive until that point.
 Unlike virus it does not replicate itself.
15

16.  Safeguards or solutions to protect computer system from
unauthorised access and threats are:
1. ANTIVIRUS SOFTWARE
 Avast, K7, AVG, Kaspersky, Quick Heal, Norton, Trend
micro, McAfree, Symantec
2. DIGITAL CERTIFICATE
3. DIGITAL SIGNATURE
4. PASSOWRD
5. FIREWALL
16

17. 2. DIGITAL CERTIFICATE
 Digital Certificate is the attachment to an electronic message
used for security purposes.
 The common use of a Digital Certificate is to verify that a user
sending a message is who he or she claims to be.
 Certification Authority (CA)
17

18.  It is an electronic form of a signature that can be used to authenticate
 the identity of the sender of a message or the signer of a document.
18

19.  A firewall can either be software based or hardware based
and is used to help in keeping a network secure.
 Its primary objective is to control the incoming and outgoing
network traffic by analyzing the data packets and determining
whether it should be allowed through or not, based on
predetermined rule set.
19

20. 20
The five types of firewall are:
1. Packet filtering firewall
2. Circuit-level gateway
3. Stateful inspection firewall
4. Application-level gateway (aka proxy firewall)
5. Next-generation firewall (NGFW)

21. Which of the following is the type of software that has self-replicating software that causes
damage to files and system?
a) Viruses
b) Trojan horses
c) Bots
d) Worms
e) Backdoors
Which of the following is a program capable of continually replicating with little or no user
intervention?
a) Virus
b) Trojan horses
c) Rootkit
d) Worms
e) Bots
Which of the following is a software that, once installed on your computer, tracks your
internet browsing habits and sends you popups containing advertisements related to the
sites and topics you’ve visited?
a) Backdoors
b) Adware
c) Malware
d) Bots
e) Spyware
21
Answer: (d)
Answer: (a)
Answer: (b)

22. What is the software called that’s designed to exploit a computer user and is a broad term
covering computer viruses, worms, Trojan, adware, etc.?
a) Backdoors
b) Key-logger
c) Malware
d) Bots
e) Spyware
What is the software called which when get downloaded on computer scans your hard drive
for personal information and your internet browsing habits?
a) Backdoors
b) Key-logger
c) Malware
d) Antiware
e) Spyware
Which of the following is a type of program that either pretends to have, or is described as
having, a set of useful or desirable features but actually contains damaging code.
a) Trojans
b) Viruses
c) Worm
d) Adware
e) Bots
22
Answer: (c)
Answer: (e)
Answer: (a)

23. _________ are computer programs that are designed by attackers to gain root or
administrative access to your computer.
a) Backdoors
b) Rootkits
c) Malware
d) Antiware
e) Spyware
The attack that focuses on capturing small packets from the network transmitted by other
computers and reading the data content in search of any type of information is ____
a) Phishing
b) Eavesdropping
c) Scams
d) Exploits
e) Denial of service
If your computer keeps rebooting itself, then it is likely that _______.
a) It has a virus
b) It does not have enough memory
c) There is no printer
d) There has been a power surge
d) It needs a CD-ROM
23
Answer: (b)
Answer: (b)
Answer: (a)

24. _________ is the action of recording the keys struck on a keyboard, typically covertly, so that
the person using the keyboard is unaware that their actions are being monitored.
a) Denial of service
b) Exploits
c) Scams
d) Keylogging
e) Spamming
______ is the part of malware such as worms or viruses which performs the malicious action;
deleting data, sending spam or encrypting data.
a) Denial of service
b) Exploits
c) Scams
d) Payload
e) Spamming
Which of the following is the key function of a firewall?
a) Copying
b) Monitoring
c) Commanding
d) Moving
24
Answer: (d)
Answer: (d)
Answer: (b)

25. A program designed to destroy data on your computer which can travel to "infect"
other computers is called a
a) infector
b) torpedo
c) hurricane
d) virus
e) disease
_____________________ is a form of virus explicitly designed to hide itself from
detection by antivirus software.
a) Macro Virus
b) Parasitic Virus
c) Stealth virus
d) Polymorphic Virus
The virus that spread in application software is called as
a) Boot virus
b) Macro virus
c) Anti virus
d) File virus 25
Answer: (d)
Answer: (b)
Answer: (c)

26. Virus, Trojan horse and Worms are
a) Able to harm the computer system
b) Unable to detect if present
c) User-friendly applications
d) Harmless applications resident on computer
Which of the following is a criminal activity attempting to acquire sensitive information
such as passwords, credit cards, debits by masquerading as a trustworthy person or
business in an electronic communication? [IBPS Clerk 2010]
a) Spoofing
b) Phishing
c) Stalking
d) Hacking
e) None of these
Junk email is called
a) Spam
b) Spoof
c) Sniffer Script
d) Spool
26
Answer: (a)
Answer: (b)
Answer: (a)

27. All of the following are examples of real security and privacy risks EXCEPT:
a) Hackers
b) Spam
c) Viruses
d) Identity theft.
_______________are often delivered to a PC through an e-mail attachment and are often
designed to do harm.
a) Viruses
b) Spam
c) Portals
d) Email messages
e) None of these
First computer virus is a
a) A hardware
b) Windows tool
c) A computer program
d) A system software
e) None of the above
27
Answer: (C)
Answer: (a)
Answer: (C)

28. The first computer virus is
a) Creeper
b) PARAM
c) The famous
d) HARLIE
28
Answer: (a)
Answer: (b)
Answer: (a)

29. 29
Answer: (a)

30. 30
Answer: (c)
Answer: (d)

31. 31
Seek Time - the time taken for a disk drive to locate the area on the disk where the
data to be read is stored.
Latency - Latency is the amount of time a message takes to traverse a system. In
a computer network, it is an expression of how much time it takes for a packet of
data to get from one designated point to another. It is sometimes measured as
the time required for a packet to be returned to its sender.
Turnaround time - the amount of time taken to complete a process or fulfill a
request.
Execution Time / CPU time - the time spent by the system executing that task.
Answer: (c)

32. 32
• Mnemonic code is used instead of remembering the hexcode of the
operations. Assembly code uses Mnemonic code so that it is easier to
program in Machine code.
Answer: (c)
Answer: (b)

33. 33
Answer: (d)
Answer: (c)
Answer: (a)

34. 34
Answer: (d)
Answer: (a)

35. 35
A multi-user operating system (OS) is a
computersystem that allows multiple users that
are on different computers to access a
single system's OS resources simultaneously, as
shown in Figure 1. Users on the system are
connected through a network.
Time-sharing is a technique which enables
many people, located at various terminals, to use
a particular computer system at the
same time. Time-sharing or multitasking is a
logical extension of multiprogramming.
Processor's time which is shared among
multiple users simultaneously is termed as time-
sharing.
Answer: (b)

36. 36
Answer: (c)
Answer: (c)
Answer: (d)

37. 37
Optical mark recognition (also called optical mark reading and OMR)
is the process of capturing human-marked data from document
forms such as surveys and tests.
They are used to read questionnaires, multiple choice examination paper
in the form of lines or shaded areas.
Answer: (d)

38. 38
Answer: (b)
Answer: (a)
Answer: (c)

39. 39
Answer: (b)
Answer: (d)
Answer: (c)

40. 40
Answer: (a)
Answer: (c)
Answer: (b)

41. 41
• Multiprogramming – A computer running more than one program at a time
(like running Excel and Firefox simultaneously).
• Multitasking – Tasks sharing a common resource (like 1 CPU).
• Multiprocessing – A computer using more than one CPU at a time.
• Multithreading is an extension of multitasking.
Answer: (c)

42. 42
Answer: (c)

43. 43
Answer: (d)
Answer: (a)
Answer: (b)
Answer: (d)

44. 44