Date post: | 08-Jun-2015 |
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COMPUTER VIRUSES
WHAT IS A COMPUTER VIRUS?
A computer virus is a small software program that spreads from
one computer to another computer and that interferes with
computer operation. A computer virus may corrupt or delete data
on a computer, use an e-mail program to spread the virus to other
computers, or even delete everything on the hard disk.
.
CHARACTERISTICS OF A COMPUTER VIRUS:
the ability to replicate itself.
the ability to attach itself to another computer file.
WORKING OF COMPUTER VIRUS
A Computer Virus needs another program in
order to be able to be activated and infect other
computers files.
For example, a virus might attach itself to a
spreadsheet program. Each time the program runs,
the virus runs too.
A file containing virus is called infested file.
TYPES OF COMPUTER VIRUSES
Stealth viruses
Use certain techniques to avoid detection.
Macro Viruses
Infects the macros within a document or template.
Polymorphic viruses
Encrypt its code in different ways
Metamorphic viruses
Rewrite themselves each time
they infect a new file.
Boot viruses
Affects boot sector of a floppy or hard disk.
Program viruses
Infect executable program files.
Multipartite viruses
A hybrid of Boot and Program viruses.
Directory Virus
Directory viruses change the paths
that indicate the location of a file
TYPES OF COMPUTER VIRUSES
VIRUS THROUGH THE INTERNET
Today almost 87% of all viruses are spread through
the internet (source: ZDNet)
87%
13%
Inter...
TROJAN HORSE
Covert
Leaks information
Usually does not
reproduce
WORMS
Spread over network connection
Worms replicate
First worm released on the Internet was called
Morris worm, it was released on Nov 2, 1988.
WHAT CAN VIRUSES DO?
Format hard disk
Copy, rename and delete files
Modify files dates and extensions
Display false message every few times
Damage data
Damage software
SYMPTOMSComputer runs slowly
Random restarts
Unknown and uninstalled icons on desktop
Icons change in appearance
System memory and disk space is reduced
New windows open up at an alarming rate
Error messages on regular basis
Files mysteriously disappear
HOW VIRUS SPREADS?
Opening and downloading an email containing virus
Networks
Connecting with network that contains virus
Removable Storage Media
Floppy discs, CDs and flash devices
Pirated Software
Installing pirated software that contains virus
WHO CREATES VIRUSES AND WHY?
Common people:
For fun
Release anger
Take revenge
For fame
Profit earners:
Antivirus market
Info attackers:
Disrupt enemy’s information and network
HOW TO PROTECT FROM VIRUS?
Latest antivirus should be installed
Antivirus software must be upgraded regularly
Unknown emails should not be opened
Unauthorized software should not be installed
Removable storage media should be scanned
Freeware and shareware software from internet
should be checked before installing
TOP SEVEN ANTIVIRAL PROGRAMS
Kaspersky Antivirus
Avira Antivirus
Mcafee Antivirus
Symantec Norton Antivirus
Bit Defender 2010
Quick Heal Antivirus
AVG Antivirus
GENERAL SECURITY TIPS Apply user-level security on file sharing
when needed.
Don't open email attachments from
unknown senders.
Use Rich Text Format files instead of
Word Documents.
Updated anti-virus program
Set the BIOS boot sequence
Write protection
Made By- Vivek Sharma
10th A
END !