• _____________ is a program that is deliberately created to cause annoyance or alter or delete data.
    • Computer Virus
  • Below are of the features of Virus
    • Replicate and spread
  • Viruses infect a variety of different subsytems on their hosts
    • TRUE
  • Classifying Viruses
    • Whether reside in Binary Executable form (.exe)
    • Data files (MS word)
    • Boot sector of the host
    • Aos Hard drive
  • Virus also classified into two types based the manner how they replicate when they are executed
    • Non Resident virus immediately search for other hosts that can be infected, infect those targets, and finally transfer control to the application program they infected
    • Resident virus do not search for hosts when they are started
  • Instead a resident virus loads itself into memory on execution and transfers control to the host program
  • The Virus stays active in the background and infects new hosts when those files are accessed by other programs or the operating system itself


Non Resident Viruses:

  • Nonresident viruses can be thought as, consisting of a finder module and a replication module
  • The finder module is responsible for finding new files to infect
  • For each new executable file the finder module encounters, it calls the replication module to infect the file

Resident Viruses

  • Resident viruses contain a replication module that is similar to the one that is employed by nonresident viruses
  • This module is not called by a finder module
  • This virus loads the replication module into memory when it is executed instead and ensures that this module is executed each time the OS is called to perform a certain operation
  • The replication module can be called for example, each time OS executes a file
  • In this case the virus infects every suitable program that is executed on the computer


Viruses types

  • Trojan
    • A virus that hides itself inside another legitimate program
    • When the program is used, the virus is released and can begin its work of replication and annoyance or damage
  • Worm
    • A program that replicates itself over and over in the computer, Aos memory untill the computer can barely function
    • One of the signs of invasion by a worm is the slowness of computers
  • Time Bomb
    • A virus which lies dormant (sleeping) until a certain date or time or for a period of time
    • At this date or time, the virus suddenly becomes active and carries out whatever task it is programmed to do
    • This can include the deletion of everything on the hard-drive
  • Logic Bombs
    • A logic bomb is similar to a time bomb, except that instead of becoming active at a certain time, it becomes active when a particular activity happens
    • Example: Instead of formatting a diskette, the virus causes the hard drive to be formatted
  • Macro-viruses
    • Micro-viruses make use of a special customization feature in applications called macros
    • Macros allow you to create miniprogrames to carry out certain tasks in your applications

Spread of Computer Viruses

Viruses are spread in a number of ways

  • Downloads from the internet
  • Pirated software
  • Exchange of diskettes
  • In attachments to emails and in emails themselves
  • In Documents, Macro-virus, described above, can be hidden in orinary documents, spreadsheets and presentations

Main Features


  • Virus is an executable program. It is not a complete program, but they are parasatic on other programs, so it enjoys all the program can get power


  • Will spread to uninfected computers from the infected computers through various channels
  • Resulting in the infected computer computer malfunction or even paralysis


  • Computer virus when it is run on the computer, it is contagious and leads to destructive activities


  • Computer virus after entering the system won’t attack at that time
  • attack can happen in a few weeks or months or even years hidden in the legal document, the infectious to other systems, without being found, latent better its presence in the system of time will be longer the infection of the virus range would be bigger


  • Generally have high programming skills
  • by infection, computer system usually can perform normal operation, the user will not feel any abnormal
  • do not seem to have in the computer what happened
  • It is because of concealment
  • Most of the virus code designed to be very short but also hide


  • Computer virus is generally targeted at specific OS
  • Example: Miscrosoft windows98, 2000 and XP
  • Once the attack is successful, it will attack
  • If the other is not Microsoft with Windows, may be UNIX, the virus will fail

Can Trigger

  • Virus has predetermined trigger conditions, these conditions may be time, date, file type or some specific data the virus is running,
  • the trigger mechanism to check whether a predetermined condition is satisfied, if met, infection or destruction of action, make the virus infection or attack, if not satisfied, the virus continues to lurk

Protective Measures

Anti-virus software

  • Prevent, detect and remove malware such as
    • Viruses, malicious, hijackers, ransomware, keyloggers, backdoors,, rootkits, trojan horses, worms, malicious ISPs, dialers, fraudtools, adware and spyware
  • Computer security including protection from social engineering techniques is commonly offered in products and services of antivirus software companies
  • Anti-virus software scans files for pieces of code called signatures, which it recognizes as part of a virus
  • Updating anti-virus software mostly involves updating the signature files
  • This should be done on frequent basis as possible
  • this is even more the case when you receive files regularly from outside sources
  • The actual antivirus program itself will be updated from time to time
  • These will updates will include additional features and improved methods of scanning
  • It is important to keep in mind that no anti-virus software is perfect
  • It is ony as good as the technique it uses for detecting viruses and the currency of the signature file
  • There is always a chance that virus will go undetected
  • However, a good anti-virus system installed on your system is essential and will usually detect most viruses
  • When a virus is detected, the software will attempt to remove the virus
  • This process is called cleaning or disinfecting.
  • it sometimes happens that the system can detect the virus but not get rid of it
  • In this case, you will usually be given the option of deleting or quarantining the infected file
  • When a file is quarantined, it is made unusable and so unable to spread the virus
  • A future update of the software may be able to remove the virus
  • if it can the quarantine is removed
  • Some of the leading antivirus software are Quick heal Antivirus, Nortan Anti Virus, Kapersky Anti-virus, McAfee Anti-virus
  • Avira Anti virus

Protective Measures

  • Use Anti-Virus software keep up-to-date
    • Check for new definition updates daily
    • Most anti-virus software can be configured to do this automatically
  • Install security patches
    • Vulnerabilities in software are constantly being discovered and they dont discriminate by vedor or platform
    • It’s not simply matter of updating windows, at least monthly check for and apply updates for all software you use
  • Use a Fire wall
    • No internet connection is safe without one
    • Firewalls are necessary even if you have a dial-up internet connection
    • It takes minutes for a non firewalled computer to be infected
  • Secure your browser
    • Many labour under the dangerous misconception that only internet explorer is a problem
    • It is not the browser you need to be concerned about nor it is a matter of simply avoiding certain types of sites
    • Known legitimate websites are frequently being compromised and implanted with malicious javascript that foists malware onto visitors computers
    • To ensire optimum browsing safety, the best tip is to disable javascript for all but the most essential of sites such as banking or regular e-commerce sites
  • Take control of your email
    • Avoid opening email attachments received unexpectedly, no matter who appears to have sent it
    • Most worms and trojan laden spam try to spoof the sender’s name
    • make sure your email client is not leaving you open to infection
    • Reading email in plain text offers important security benefits that more than offset the loss of pretty colored fonts
  • Treat IM suspiciously
    • Instant messaging is a frequent target of worms and trojans
    • Treat it just as you would email
  • Avoid P2P and distributed file sharing
    • Torrent kazaa and at least done other file sharing networks exist
    • Most are free
    • And all are rife with trojans, virus, worms, adware, spyware and every other form of malicious code imaginable
    • There is no such thing as safe anonymous file sharing
  • Keep abreast of internet seams
    • Criminals think of clever ways to separate you from your hard earned cash
    • Don’t get fooled by emails telling sad stories or making unsolicited job offers or promising lotto winnings
    • Likewise, beware of entail hidden as a security concern from your bank or other e-commerce site
  • Don’t fall victim to virus hoaxes
    • Dire-sounding entail spreading fear, uncertainty and doubt about non-existent threats serve only to spread needless alarm and may even cause you to delete perfectly legitimate files in response






  • What is “Trend Micro”?
    • It is anti-virus software
    • It is just a program
    • It is virus program
    • None of the above
    • Ans: C
  • What is the name of the viruses that fool a user into downloading and/or executing them by pretending to be useful applications?
    • Cracker
    • Worm
    • Trojan horses
    • Keylogger
    • Ans: C
  • The virus that spread in application software is called as
    • Boot virus
    • Macro virus
    • File virus
    • Anti virus
    • Ans: B
  • How does a Le-Hard virus come into existence?
    • Hardware
    • Software
    • FRIDAY 13
    • Command.Com
    • Ans: D
  • What is the virus that spread in computer?
    • It is hardware
    • It is system software
    • It is a computer program
    • It is a windows tool
    • Ans: C
  • What kind of attempts is made by individuals to obtain confidential information from a person by falsifying their identity?
    • Computer viruses
    • Spyware scams
    • Phishing scams
    • None of the above
    • Ans: C
  • When does the time bomb occur?
    • During a particular logic and data
    • During a particular time
    • During a particular data or time
    • None of the above
    • Ans: C
  • Delayed payload of some viruses is also called as
    • Time
    • Bomb
    • Anti-virus
    • None of the above
    • Ans:B
  • What is the first boot sector virus?
    • Brain
    • Mind
    • ELK cloner
    • None of the above
    • Ans: A
  • What is the name of first computer virus?
    • The Famous
    • HARLIE
    • PARAM
    • Creeper
    • Ans: D
  • The difference between a virus and a self-replicating program which is like a virus is that rather than creating copies of itself on only one system it propagate through computer network. What is the self replicating program called?
    • Keylogger
    • Cracker
    • Worm
    • All of the above
    • Ans: C
  • What is anti-virus?
    • It is a computer
    • It is a program code
    • It is a company name
    • It is an application
    • Ans: B
  • It infects the program files as these have simple formats to which viruses can be attached
    • Program Virus
    • Boot Virus
    • Multiparatite virus
    • Ans: A
  • Virus that infects the boot sector of the harddisk and if infects the OS which makes the hard disk completely useless
    • Program Virus
    • Boot Virus
    • Multiparatite virus
    • Ans: B
  • Which of these are harmful effects of viruses
    • Damage data files
    • Increasing the files size by attaching themselves to files
    • Slowing down the system by occupying most of the memory space
    • All of these
    • Ans: D
  • Alien, Acid rains and amoeba are the examples of
    • Program Virus
    • Boot Virus
    • Stealth virus
    • None of these
    • Ans:A
  • Silent 53 and Fun love Devil are the examples of
    • Stealth Virus
    • Boot Virus
    • Multiparasite virus
    • Macro Virus
    • Ans:A
  • It is a type of computer virus to that is encoded as macro embedded in a document
    • Stealth Virus
    • Boot Virus
    • Multiparasite virus
    • Macro Virus
    • Ans:D
  • Virus that places its own codes and commands into a computer’s DOS Boot sector or Master Boot Record (MBR)
    • Stealth Virus
    • Boot Sector Virus
    • Multiparasite virus
    • Macro Virus
    • Ans:B
  • This memory usually resides inside the memory and is popularly known as File Virus
    • Stealth Virus
    • Boot Sector Virus
    • Program Virus
    • Macro Virus
    • Ans:C
  • It is a program which performs  similar destructive activities, but can damage files, place virus on our computer or break passwrds but it is not a virus since it doesnot replicate or spread like virus
    • Trojan Horses
    • Stealth Virus
    • Boot Sector Virus
    • Program Virus
    • Ans: A
  • A computer program that copies itself to another computer across the internet is called
    • Worms
  • Computer software it identifies and removes computer viruses
    • Antivirus
  • Quick Heal, Nortan, AVG, MC free are the examples of
    • Antivirus
  • Another name for Computer virus is known as
    • Vaccine
  • Computer virus is usually hidden in a
    • OS
    • App program
  • When the computer virus start to impact the data it is known as
    • Virus infection
  • Another name for free computer software is
    • Public domain software
  • 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.
    • Trojans
    • Viruses
    • Worm
    • Adware
    • Bots
    • Ans: A
  • Which of the following is the type of software that has self-replicating software that causes damage to files and system?
    • Viruses
    • Trojan horses
    • Bots
    • Worms
    • Backdoors
    • Ans: D
  • _________ 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

    • Ans:D
  • 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

    • Ans:B


  • 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

    • Ans: E


  • _______ 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

    • Ans: B


  • _______ 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

    • Ans:D


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