Computer Viruses

MALWARES A software designed

to infiltrate or damage a computer system without the owner's informed consent.

A fusion of two words: MALICIOUS and SOFTWARE

Examples of MALWARES

Computer viruses

Worms

Trojan horses

Spyware

Dishonest adware

WHAT IS A COMPUTER VIRUS?

Computer Virus is a computer program, designed as a prank or a sabotage, that replicates itself by attaching to other programs and carrying out unwanted and sometimes damaging operations.

Some NOTES on VIRUSES…

Viruses are computer programs A virus can only spread from one

computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or the Internet, or by carrying it on a removable medium such as a floppy disk, CD, or USB drive.

Some NOTES on VIRUSES…

Viruses are sometimes confused with computer worms and Trojan horses.

The terms virus is sometimes used to refer to other types of Malwares.

WHAT IS A WORM? a self-replicating

computer program.

it uses a network to send copies of itself to other nodes (computer terminals on the network) and it may do so without any user intervention.

Unlike a virus, it does not need to attach itself to an existing program.

WHAT IS A TROJAN HORSE?

any program that invites the user to run it, but conceals a harmful or malicious payload.

The payload may take effect immediately and can lead to many undesirable effects

they are often referred to as “time bomb” programs

WHAT IS A SPYWARE? a computer software that is

installed secretly on a personal computer to intercept or take partial control over the user's interaction with the computer, without the user's informed consent.

can collect various types of personal information; can also interfere with user control of the computer in other ways, such as installing additional software, accessing websites blindly that will cause more harmful viruses,

WHAT IS A ADWARE? advertising-supported

software

any software package which automatically plays, displays, or downloads advertising material to a computer

Some types of adware are also spyware and can be classified as privacy-invasive software.

(Just some of the) HARM COMPUTER VIRUSES CAN DO …

Overwrites boot sector

Formats all/part of the disk

Corrupts programs/data files

Causes harm to the network

WHO WOULD CREATE A COMPUTER VIRUS

THE WHIZ KID

THE KSPs

THE TERRORIST

THE BUSINESSMAN

THE RESEARCHER

SYMPTOMS of VIRUS INFECTION

The computer runs slower than usual.

The computer stops responding, or it locks up frequently.

The computer crashes, and then it restarts every few minutes

The computer restarts on its own. Additionally, the computer does not run as usual.

SYMPTOMS of VIRUS INFECTION

Applications on the computer do not work correctly.

Disks or disk drives are inaccessible.

You cannot print items correctly.

You see unusual error messages.

SYMPTOMS of VIRUS INFECTION

You see distorted menus and dialog boxes.

There is a double extension on an attachment that you recently opened, such as a .jpg, .vbs, .gif, or .exe. extension

An antivirus program is disabled for no reason. Additionally, the antivirus program cannot be restarted

An antivirus program cannot be installed on the computer, or the antivirus program will not run.

SYMPTOMS of VIRUS INFECTION

New icons appear on the desktop that you did not put there, or the icons are not associated with any recently installed programs.

Strange sounds or music plays from the speakers unexpectedly.

A program disappears from the computer even though you did not intentionally remove the program.

Some elusive viruses won’t show any symptoms at all

GUIDE for a VIRUS FREE COMPUTING

Know your computer

Keep original copies of your executable programs in a safe place and backup data files regularly

Control system access

GUIDE for a VIRUS FREE COMPUTING

Scan all foreign diskettes/ removable storage you plan to use

Use only software from reliable sources

Maintain a library of anti-virus tools, utilities, diagnostics, etc.

GUIDES for a VIRUS FREE COMPUTING

If possible, have the file attributes of your important programs set to read-only to prevent accidental overwriting

If you suspect disk virus infection, consult a reliable adviser.

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