Computer virus & its cure
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Transcript of Computer virus & its cure
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 ??