Computer Security & Virus

The satisfaction and the joy of getting a new PC is all killed when the PC is affected by the Virus. It is one of the greatest fears among the computer users especially the new ones. Viruses are those malicious softwares designed by other users to destroy and get access to other computers. This process is repeated by them. After the creation of the virus, it is distributed by means of shareware, e-mail, pirated software, P2P programs and others where users can share data.

First written in 1982 by Rich Skrenta, a school student, the virus is transported to other computers by copying itself to a floppy diskette or monitoring floppy drive. At the infection of the floppy diskette, the other computers get infected. Computer security is also threatened by malwares, Trojans and spywares. The users can effectively prevent it by installing antivirus program.

Contraction of viruses :
Earlier, a majority of the computer viruses were contracted from those users who used to share data by means of floppy diskettes. As the internet has gained popularity, viruses have come to be contracted via e-mail and software downloading and even by P2P sharing.

Virus properties :
Infection of a computer is possible even when the files are just copied. In case of the memory resident viruses, the virus attaches itself to memory as soon as the diskette or the program is loaded into the memory. Then it becomes capable of infecting a file on the computer that you can access.

1. Can be Polymorphic :
As viruses can modify their code, they have similar variants and so they are polymorphic.

2. Can be non-memory or memory resident :
When the virus loads into memory first and then infects the computer, it is a resident virus or otherwise when the virus code is executed on every consecutive opening of the file, it is non resident.

3. Stealth virus :
Stealth virus attaches itself to the files on computer and then attacks it which enables it to spread rapidly.

4. Viruses carry other viruses :
This makes the virus even more lethal in nature. When virus carries virus, a particular section of the computer is infected by the primary virus.

5. No detection of outward signs :
The viruses are capable of hiding the changes such as modification of files, etc.

6. Viruses stay even after formatting :
Certain parts where the virus affects can be reinfected even if the computer is completely erased. e.g. CMOS battery.

How are files affected by Virus :

1. The virus has the capability of infecting of any file type such as attack .com, .sys, .exe, .bin, .pif or any other data files.
2. The viruses increase the file size when it infects the files.
3. The viruses delete the files when they are run
4. Even when the viruses cannot destroy random data, they are capable of corrupt the files randomly
5. The viruses have the capability to convert .exe files to .com files.
6. The viruses are designed to reboot, freeze and even abnormal running of programs by the computer.

• Deleted files.
• Increase disk access time.
• Various messages in on programs or files.
• Increases file size.
• Cause system to hang
• Changes volume label.
• Alter the system date /time
• Extended boot times.
• Display pictures.
• Various type of error messages