Presented by:

Md. Tamim Ahmed ID:LL.B-052 08731Md. Wahidur Rahman ID:LL.B- 052 08790

PRESENTATION ON

COMPUTERVIRUS & ITS CURE

Content Details

What is a virus? Who creates/writes viruses ? Type of viruses Major Types of Viruses Boot Sector Virus Program/File Infector Worms Macro Virus Trojan Horses

Removal of Some Common Viruses Prevention & cure of computer viruses Some anti-viruses software Conclusion

What is computer virus?

Computer viruses are a type of software program that, like a biological virus, reproduces and spreads itself

Some virus may display only a message on the screen, others may slow down the Pc

They can also erase files or even format your floppy or hard disk and crash the system.

Who creates/writes viruses ?

PSYCHO CASES FOR FUN

TO TAKE REVENG

RELEASE ANGER

INFO ATTACKERS

PROFIT EARNER VIRUS / ANTIVIRUS

MARKET

Type of viruses

There are about millions of viruses present & daily 6 to 7 new viruses are found

The following are the types of viruses:

Boot sector Virus, Program/ File Infector, Trojan Horses, Worms, Macro Virus, Polymorphic Virus,, Companion Virus, FAT Virus, Logic Bombs, Spyware, Adware, Multipartite virus, Stealth virus etc.

MajorTypes of Viruses

Virus

Boot Sector Virus

Program/

File Infector

WormsMacro

VirusesTrojanHorses

The boot Sector virus affects

the booting process of the

infected computer system.

thus causing slow start up and

shut down process

Boot Sector Virus

Program/File Infector virus

Becomes active when the

program file carrying the

virus is opened.

usually with below extensions

.BIN .COM

.EXE .OVL

.DRV

Worms

A computer worm is 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. Worms always harm the network (if only by consuming bandwidth), whereas viruses always infect or corrupt files on a targeted computer.

Worm Propagation

Leverage Network Connectivity

10

These type of virus

infects word , excel,

PowerPoint, access and

other data files. Once

infected repairing of

these files is very much

difficult.

Macro Virus

Trojan horses

A Trojan horse is a program that unlike a virus contains or installs a malicious program (sometimes called the payload or 'trojan').

The term is derived from the classical myth of the Trojan Horse.

Trojan horses may appear to be useful or interesting programs to an unsuspecting user, but are actually harmful when executed.

The famous usage in hacking.

Trojan

Two examples for Viruses

Melissa Type : Macro virus

I Love YouType : worm

The functional logic of a virus Search for a file to infect.

Open the file to see if it is infected.

If infected, search for another file.

Else, infect the file.

Return control to the host program.

16

Virus

V

Virus – Needs a host

17

Virus Propagation

Leverage User Connectivity

Cure of computer viruses

Removal of Some Common Viruses We can remove some of the common viruses

without help of any antivirus Program.

e.g.- New Folder.exe

Autorun.inf ( from PDs etc)

New Folder.exe

It looks just like an folder but actually it is a .exe file.

Try to deleting the file.It will delete if you

haven’t executed it, if you’re unable to delete it.

Go to Task manager ( by pressing ctrl+shift+del )

Go To Process TAB Go to Process Tab and try finding that the process for the exe file and end the process. Then Go to the same folder containing the exe file and delete it. Then Open Search and try finding the .exe files of same size and delete them all.

Continued …

Removal of Autorun.inf

Open Run dialog Box. Type in “CMD” press ENTER.

Continued …

The Command Prompt will Open Now. In Command prompt go to the drive containing Autorun.inf

Now Type In “ attrib –h –s –a” and press enter.

Continued …

This will remove drives attributes for all Hidden, System files.

Now Type “ Del autorun.inf” and press ENTER.

The Virus has been Successfully Removed.

Anti-Virus

Prevention & cure of computer viruses

Since virus can cause extensive effect to your important files,possible steps must be take to prevent attack on your pc

If you use floppy disk to boot your pc then write protect it

Make backups of your impotent files in floppy or cd and keep it in a safe place you will need it later

Prevention & cure of computer viruses

Install an Antivirus software Regularly update the program Open email attachment files only if you are

expecting the attached files, or the sender is known and has confirmed sending the file

Try to avoid downloading and installing software from the Internet

Install only registered copies of software on the system

Some anti-viruses software

Conclusion

I think we should not use the pc without any antivirus security as it may cause damage to our important data

Do not copy or transfer any data or file without scanning the disk.

Thank You !!

Any Question ??