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What Is Computer Virus | Types Of Computer Virus | Computer Virus Names Best Information Computer Virus
What is computer virus – Computer virus is such a powerful program of some instructions, which starts controlling the computer in its own way. These virus programs are associated with any normal computer program that is being used on the computer and through them enter the computer and fulfill their purpose i.e. to damage the data. With their infective effect, they damage or destroy all the programs they come into contact with.
The main purpose of computer virus programs is to affect only the data stored in the computer’s memory and all the programs that come in contact with their infection. Just as a viral infection or viral fever almost brings the functioning of the human body to a standstill, in the same way, a computer virus causes the internal functioning of the computer to come to a standstill. Like any microscopic germ, this virus program continues to increase its number at a very rapid rate through the process of self-replication.
What are the Symptoms of Computer Virus Programs
Characteristics of Virus Programs – Any computer program affected by virus causes unintentional and unwanted interruptions, mistakes and many other problems in its normal working style. These can also destroy the data stored in the computer’s memory. It depends on the manufacturer of that virus program. All computer virus programs are written primarily in assembly language or a high-level language such as Pascal or C. The following characteristics are found in all virus programs-
It is a very subtle program which makes it very difficult to detect them. Attaching to another program or replacing other programs, for example, a virus named c-usher lifts the boot-strapped program from the zero sector on the disk and re-installs it elsewhere. Zero sector gets established in its place. Infection – This is the process by which the virus keeps on spreading continuously in a qualitative process.
Creating difficulties in the execution of other working programs, for example – displaying a particular message at a particular time, destroying or damaging all the programs and data present in the disk at a particular time or date, etc.
Signs Of Computer Virus Infection
If the computer has been affected by virus attack, its identification is obtained from these signals-
1- Depletion of available memory (RAM) without loading the running program into memory.
2- Change in size of working file without any reason.
3- Automatically change the number of files.
4- The ‘key’ board suddenly started working undesiredly.
5- The computer hangs (stuck).
6- The computer starts giving many types of undefined and unwanted inaccuracy messages.
7- Automatically decrease the speed of the computer. 8- Change or destruction of computer or data.
Type Of Computer Virus
Generally three types of virus programs are found
1) Boot Sector Virus
2) File Virus
3) Other Virus
Boot Sector Virus
Boot Sector Virus – This type of virus spreads its infection in the zero sector of the boot floppy of the hard disk or disk operating system (DOS). These viruses also change the partition table present in the hard disk. This type of virus is first installed in the memory instead of the program of the operating system as soon as the computer is started.
boot virus can also be installed in the computer’s memory when attempting to boot a computer from any other disk (which is not a boot disk), as the operating system attempts to read the zero sector disk of the computer disk. while reading virus programs Non-system will display disk error, but, by then the virus may have been installed in the memory. Now when the boot disk is inserted in the computer, the virus located in the computer memory enters the disk (if the disk is not write protected).
File Virus – As the name suggests, this type of virus enters the program files of the computer. These viruses prey only on COM, EXE, SYS, OVL and BIN files. These effects are commonly seen on EXE and COM files. This virus attaches itself to the files. This virus itself executes before its effect, later allows that file to be executed. It also affects the size of these files. Here are the details of file viruses-
1) 1701, 1704, 1744 Virus- All these viruses affect COM files.
2) April First- This virus affects EXE files.
3) Jerusalem version B- This virus affects EXE and COM files.
4) 648 Virus- This virus affects COM files.)
5) Data Crime 1208, 1168 – All these viruses affect COM files.
6) FRIDAY 13- This virus affects COM and EXE files. It increases the size of these files to 1808 bytes and the virus is automatically destroyed on Friday the 13th.
7) 8290 virus – This virus finds the numbers 82 and 90 in the disk and when it does not find these numbers in the boot sector, it replaces the boot record elsewhere and the system stops booting.
8) Lee-Lard Virus- This virus infects the COMMAND.COM file of DOS. This virus has a calculator which makes a self copy on giving simple command of DOS, which we are using for some of our work. Then it destroys all the programs and data on the disk along with the File Allocation Table.
9) Raindrop Virus- This virus also affects COM files. Due to the effect of this virus, on giving dos command, the letter starts dripping or flowing downwards like rain. COM files get damaged due to the effect of Die Hard-to-This File Virus and at the time of execution of any program, either this program is not executed or the computer gets booted. Some viruses infect files as well as infect the boot sector, such as the 648 virus.
Apart from the above mentioned boot sector viruses and file viruses, there are also some other viruses which cause heavy damage to the programs and data stored in the computer.
Trojan – Other virus programs contain Trojan programs. These programs give the illusion of being different types of word processors or data-base programs at the time of use, but in reality they are all viruses. Just like recently, a major program to disseminate measures to prevent AIDS disease has been loudly in the market.
Sold, but later it was found that this is not a training program but a known virus program. .
Worm – This virus has the ability to cover long distances like any biological insect. They mainly affect long computer networks with infections. These are state-of-the-art virus programs, in which microscopic instructions are given, by which they are capable of performing all kinds of actions. In this way, virus infection occurs mostly on computer networks based on the Unix operating system.