what is computer virus and how to protect yourself from viruses?

Viruses

techeeINDIA

Computer virus is a malicious program that requires a host and is designed to make a system sick, just like a real virus. Viruses can spread from computer to computer, and they are far more malicious. Broadly three types if viruses are: -

1.        File infectors – attach themselves to a program file.

2.       Boot sector viruses – install themselves on the beginning tracks of a hard drive.

3.       Macro viruses – infect data files.

Most viruses are spread by e-mail attachments and warm them to be suspicious of any files attached to unsolicited messages. The following are characteristics of a computer viruses.

Ø  It is able to replicate.

Ø  It requires a host program as a carrier.

Ø  It is activated by external action.

Ø  Its replication ability is limited to the (virtual) system.

How computer viruses spread?

Computer viruses move from computer to computer by attaching themselves to files or boot records of disks and diskettes. These days it is not uncommon to find them in e-mail attachments and other programs that can be downloaded from the internet.

A virus is a relatively passive agent that can be travel from one file to another file on the same computer if the infected file is executed, from computer memory to a file on disk, on a disk that is carried one computer to another (some companies prohibit floppy drives, thereby preventing users from copying information onto their computers), on e-mail attachment executable files, and over a modem or network connection.

Damage that viruses cause

techeeINDIA

Viruses main objected is to make your system unstable and cause harm to data. Mainly these cause damage in many ways: -

Ø  Can destroy file allocation tables (FAT) and lead to the corruption of an entire file system, resulting in the need to fully reinstall and reload the system.

Ø  Can create bad sectors on the disk, destroying parts of programs and files.

Ø  Can decreases the space on hard disks by duplicating files.

Ø  Can format specific tracks on the disks or format the entire disk.

Ø  Can destroy specific executable files and alter data in data files, causing a loss of integrity in the data.

Ø  Can cause the system to hang so that it does not respond to any keyboard or mouse movements.

   ALSO CHECK: -what is port and its types ?

Trojan horses

A trojan horse is code hidden in a program such as a game or spreadsheet that looks safe to run but hidden side effects. When the program is run, it seems to function as the user expects, but in actually it is destroying, damaging, or altering information in the program in which to embed itself. An example of a Trojan horse would be a Christmas executable that, when executed, pops up with an animated figure of Santa Claus and a caption saying “Merry Christmas”. In the background, extra code could be deleting files or performing others malicious actions.

How Trojan horse spread   

Trojan horse generally are spread through e-mail and exchange of disks and information between computers. Worms could also spread Trojan horses.

Damage caused by Trojan Horses

The damage that Trojan horses cause is much the same as what a virus causes. Most of the time the users are unaware of the damage it is causing because of the Trojan horse’s masking effects.

Worms: -

A worm is a program designed to replicate. The program may perform any variety of additional tasks as well. The following are characteristics of a worm:

Ø  It is able to replicate.

Ø  It is self-contained and does not require a host.

Ø  It is activated by creation process (it needs a multitasking system).

Ø  If it is a network worm, it can replicate across communication links.

Worms are program that run independently and travel from computer to computer across network connections. Worms may have portions of themselves running on many different computers. Worms do not change other program, although they may carry other code that does.

How Worms Spread: -

Worms are autonomous agents capable propagating themselves without the use of another program or intervention or action by a user. Worms are found primarily on computers that are capable of multitasking and are connected to network.

Damage that Worms can cause: -

Most worms disrupt services and create system management problem. Some worms scan for passwords and other loopholes and then send the information back to the attackers. In some causes worms can install Trojan horses or viruses that cause damage to the system.

Spam: -

Spam refers to electronic junk mail or junk new group posting. Some people define spam even more generally as any unsolicited e-mail. Merriam -Webster dictionary defines spam as unsolicited usually commercial e-mail sent to a large number of addresses.

Avoiding spam: -

Ø  One way to help avoid spam or junk mail is to create a filter that finds and does something to email that you suspect is spam.

Ø  Another tip is not to register yourself with true id to sign up for things on the Internet. These places often share that e-mail address with other companies that then send you spam.

How to protect against computer virus : -

techeeINDIA

Virus prevention is not a difficult task. All you need to be is extra careful and ensure to lead virus free computing life.

Ø  Never use a “foreign “disk or CD without scanning it for viruses.

Ø  Always scan files downloaded from the internet or other sources.

Ø  Never boot your PC from a floppy unless you are certain that it is virus free.

Ø  Write protect your disks.

Ø  Use licensed software.

Ø  Password protect your PC to prevent unattended modification.

Ø  Make regular backups.

Ø  Install and use antivirus software.

Ø  Keep antivirus software up to date.  

                                       Jai Hind