Introduction to Computer Virus

Introduction: 1949, John von Neumann says “Theory self altering automata” it result from mathematic scientist research.

1960, Lab BELL (AT & T) trying the theory by making of mind-game. They make game it can copy itself, modifying and infect program build by opponent. The program it could still survive and infect the other program will be the winner. This game become a favorite game but the program become more dangerous, so they control this game carefully. 1980,The program now called virus and it spreading out from Lab, and start spreading in public computer.

Virus is “a program that can infect other programs by modifying them to include a slightly altered copy of it-self. A virus can spread throughout a computer system or network using the authorization of every user using it to infect their programs. Every programs that gets infected can also act as a virus that infection grows”.

Characteristics of Computer Viruses:

1. Cannot exist in a viable form, apart from another (usually legitimate) program.

2. Propagates when the host program is executed.

3. Has an incubation period, during which no damage is done.

4. After incubation period, begins to manifest its behavior.

Where viruses can hide:

1. In the "boot" sector of disk. This is a small program which runs whenever the computer is "booted" from the diskette, whether or not the diskette is "bootable.".

2. Attached to any program: shareware, commercial or public domain.

3. Embedded in the hidden system files IO.SYS and MSDOS.SYS on the boot disk or drive.

4. Same as #2, but pay SPECIAL ATTENTION to the file COMMAND.COM on the boot disk or drive.

5. The "partition table" on a hard drive. (This DOES contain executable information, since it is attached to the "Master Boot Record" which is consulted at boot-up to determine whether to boot DOS, OS/2, UNIX, etc.)

Types of computer virus.

Based upon the areas in your computer that these viruses attack, they are of the following varieties:

1. File infector viruses

2. Boot sector viruses

3. Macro viruses

4. Network viruses

5. Multi-partite viruses

6. Worms

How viruses are spread:

1. Trading, copying or pirating software on diskettes without knowing the source.

2. Software salesmen giving demos on your computer from their diskettes.

Impact of virus on computer system:

1. Programs: Some viruses may impair your certain computer programs and applications. As a result, you may not be able to access the software or operate it smoothly. Sometimes the infected programs may yield inaccurate output; printer may not work properly, etc.

2. Files: There are viruses that may modify, corrupt or delete files in your machine owing to which you may not be able to access them. If the files happen to be system or program files then your machine’s activity may be affected and your computer may even crash.

3. Hard disk: Some viruses may attack the data present on your computer’s hard disk, resulting in its crash. You may need to reformat the disk in such cases.

4. perational impact: Some viruses may not apparently harm your system’s integrity and may limit themselves to displaying text messages, images, audio and video. They however, consume your machine’s memory which slows down the system significantly.

5. Reinstall: Some computer viruses are designed in the gravest way possible. They cannot be uninstalled easily from your system and some reinstall themselves even after they have been removed. It therefore becomes all the more crucial that you have effective and updated anti-virus software instituted on your system. Antivirus removes and checks the entry of all the viruses, including those trying to reinstall, it can detect in your machine.

6. Speed: Your system may slow down under the influence of viruses as they consume your system’s memory for their execution.

7. Operation: Computer may hang frequently or may display erratic error messages.

8. Booting: Your system may suddenly restart and at times may not load properly. In few cases, you may not be able to access your disk drives.

9. Aplications: Viruses may modify, damage or delete your program files and system files because of which applications on your system may not be able to work appropriately.

10. Peripherals: Some viruses may impact device driver software in your computer resulting in the relevant operational issues. For example, disturbed software setting for printer may impair its function.

11.Display: At times your computer’s display may be deformed and you may notice altered images of dialog boxes and menus.

Protection from virus attacks:

1. Anti-virus software: Installing anti-virus software removes all the viruses it ‘detects’ while also prohibiting the entry of new ones in the system.

2. Firewall: This is software or hardware that prohibits the entry of any undesirable file or software into your system.

3. Internet download: Avoid downloading freeware or programs from the internet. They may contain network virus.

4. System update: It’s important to keep your system updated.

5. Awareness: Keep yourself posted on the latest in PC threat so that you brace your machine accordingly.

The only secure computer is one that's

disconnected from all networks

Especially ‘POWER’...