Computer Virus - Computer Fundamental

Computer Virus

One of the biggest fears among new computer users is being infected by a computer virus or programs designed to destroy their personal data. Viruses are malicious software programs that have been designed by other computers used to cause destruction and havoc on a computer and spared themselves to other computers where they can repeat the process.

A computer virus is a software program that was first written by Rich Skrenta in 1982 was a 15-year old high school student. Known as the elk cloner this virus spread to other computers by monitoring the floppy drive and copying itself to any floppy diskette that was inserted into the computer. Once a floppy diskette became infected it would infect all other computers that disk was inserted into, each computer that was infected would then infect every floppy diskette inserted into it. A computer that was infected would also display a short poem on every 50th boot.

Computer users can help protect themselves against computer viruses, malware, and other computer security threats by installing an antivirus protection program.

What is a computer virus?

A computer virus is a footwear program that has been intentionally created to cause a user grief, spare to other computers, or destroy data on an individual’s computer. To help prevent a computer from becoming infected by a virus, software developers have developed anti-virus programs that stay active on the computer helping to protect it. It is important to realize that many computers do not come pre-loaded with these already installed and that if computers do come with these programs, the programs may expire within 90 days.

How viruses may affect files

• Viruses can affect any files; however, usually attack .com, .exe, .sys, .bin, .pif, or any data files: Viruses have the capability of infecting any file; however, will generally infect executable files or data files, such as word or excel documents that are opened frequently and allow the virus to try infecting other files more often.
• Increase the size of the file, however, this can be hidden: When infecting files, virtues will generally increase the size of the file; however, with more sophisticated viruses these changes can be hidden.
• It can delete files as the file is run: Because most files are loaded into memory, once the program is in memory the virus can delete the file used to execute the virus.
• It can corrupt files randomly: Some destructive viruses are not designed to destroy random data but instead randomly delete or corrupt files.
• It can because write protect errors when executing .exe files from a write-protected disk: Viruses may need to write themselves to files that are exculpated; because of this, if a diskette is write-protected, you may receive a write protection error.
• It can convert .exe files to .com files: Viruses may use a separate file to run the program and rename the original file to another extension so the .exe is run before the com.
• It can reboot the computer when executed: Numerous computer viruses have been designed to cause a computer to reboot, freeze, or perform another task not normally exhibited by the computer.

What viruses may do to a computer

Below are possibilities you may experience when you are infected with a virus. Remember that you also may be experiencing any of the below issues and not have a virus.

• Deleted files
• Various messages in files or on programs
• Changes volume label
• Marks clusters as bad in the fat.
• Randomly overwrites sectors on the hard disk.
• Replaces the MBR with own code
• Create more than one partition.
• Attempts to access the hard disk drive, which can result in error messages such as: invalid drive specification.
• Causes cross-linked files.
• Causes a “sector not found” error.
• Cause the system to run slow.
• Logical partitions created, partitions decrease in size.
• A directory may be displayed as garbage.
• Directory order may be modified so files, such as com files, will start at the beginning of the directory.
• Cause hardware problems such as keyboard keys not working, printer issues, modem issues etc.
• Disable ports such as LPT or COM ports.
• Causes keyboard keys to be remapped.
• Alter the system time/date.
• Cause system to hand or freeze randomly.
• Cause activity on HDD or FDD randomly.
• Increase files size.
• Increase or decrease memory size
• Randomly change file or memory size.
• Extended boot times.
• Increase disk access times.
• Cause computer to make strange noises, make music, clicking noises or beeps.
• Display pictures.
• Different types of error messages.

Detecting viruses

The recommended method of detecting and cleaning the computer from any computer viruses or other malware is an antivirus protection program.

Alternatively, a user can look at various aspects of the computer and detect possible signs indicating a virus is of the computer. While this method can be used to determine some viruses, it cannot clean or determine the exact virus you may or may not have and is not recommended.

Virus myths

Below are some comments we’ve come across that are common misconceptions when it comes to computer viruses and other malware.

• “If I download a file onto a disk, I don’t have to worry about viruses” - This is not true, just because you’ve placed a file on a diskette or moved a file from a diskette to your hard drive does not mean that your computer cannot be infected. Many viruses are memory residents and capable of loading themselves into memory once a diskette is placed in the computer.
• “If I buy sealed software I don’t have to worry about viruses.” Or “If I just buy registered software I don’t have to worry about viruses.” : This is not always true, just because the program may be surrounded by plastic doesn’t mean that it cannot be infected with a virus. When a software program is saved onto a diskette or disc if that computer or program is infected the virus will attach itself. Although this issue very rarely occurs it is still a possibility.
• “If I don’t download anything off of the Internet I don’t have to woes about viruses.”: This is definitely not true. Although most companies and web stars will scan the files for viruses before they make them available to download some may not. In addition, many people crate a site or a file to download with the intention of spreading a virus, spyware, Trojan horses, or other malware.
• “If I just read my e-mail, I will not have to worry about viruses.”:  Not true; there are viruses out there that are distributed through e-mail; also files can be attached with e-mail and if executed can infect the computer. Today this is one of the most common ways computer viruses spread around the world.
• “If I don’t get on the internet I don’t have to worry about viruses.”: This, unfortunately, is not the case. Although many viruses are spread over the Internet today it is still possible to contract a computer virus from any diskette or disc you put in the computer.
• “You can contract viruses from just looking at web pages.”: Not true. However, you can contract a virus if you download and execute a file from that web page. In addition, spyware and other scripts can be executed from just viewing a web page. Although these programs are not designed to delete files on your computer they should be considered a privacy violation.

McAfee Virus Scan Anti Virus

VIRUS SCAN

McAfee Virus Scan is one of the most popular Virus scanning software packages available today. McAfee is designed to load into memory each time the computer boots, and if and when a virus attempts to infect your computer, has the capability of detecting that virus and removing it from the file and/or system.

Morton Antivirus Anti Virus

NORTON ANTIVIRUS 2000

Norton Antivirus 2000 6.0 is the latest edition of the Norton Antivirus protection utilities, with improved support over the previous versions of Norton Antivirus, including features such as scanning e-mail, files within zip files, and all other major executable files for viruses automatically when running.

If format or erase my hard drive will it remove a virus?

If your computer is infected with a virus formatting or erasing the hard disk drive and starting over will almost always remove any type of virus? however, keep in mind if backups have been made that contain the virus, other media or drives connected to the computer have a virus, your computer is connected to another computer on a network with a virus, and/or the virus is stored on some other types of software you use with your computer it can become re-infected if not properly protected.

Computer Acronyms, Terms and abbreviations

BIO – Basic Input Output System. This is the basic set of instructions that tell the computer how to act. Most computers have these instructions built into a chip that plugs into the motherboard.

Bit – Short for binary digit; either a 1 or 0; the smallest unit into which digital information may be broken.

BPS -  Bits per Second A measure of the speed of data transmission; the number of bits of data that can be transmitted each second. Modems are generally measured by their BPS rate (14.4K – 1440 BPS, 28.8K – 28800 BPS)

CMOS – Acronym “Complementary Metal Oxide Semiconductor” A CMOS computer circuit consumes very little power and is used in computers to keep track of the system setup information, data, time, type of disk and hard drives, etc. that a computer has installed. The CMOS information is powered by the computer’s onboard battery. So if the onboard battery fails, the information in CMOS is lost.

Floppy Disk - A removable storage medium that is used in conjunction with a floppy drive, usually 5.25-inch or 3.5-inch in size.

GB – Acronym “Gigabyte” 1,00 Megabytes. A measure storage space. Hard Crives are measured in GB capacity.

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Computer Virus - Computer Fundamental - IndianEchnoEra

Questions for this unit:

1. What is virus?
2. What is computer virus?
3. How do viruses may affect files?
4. What do viruses may do to a computer?
5. How to detect viruses?
6. What are virus myths?
7. McAfee virus scam anti virus
8. Norton antivirus
9. If I format or erase my hard drive will it remove a virus?
10. What will be happed if I format to our virus effected drive?
11. Should we format or erase to our virus affected drive or computer?