Definition of 'Computer Virus'

Definition: A computer virus is a malware program that is loaded on the user's computer without the user's knowledge and performs malicious acts.

Explanation: The term "computer virus" was originally defined by Fred Cohen in 1983. Computer virus does not occur naturally. They are always caused by people. However, once created and released, their spread is not controlled directly by humans. After entering the computer, the virus connects itself to another program so that execution of the host program triggers virus action. It self-replicates, inserts itself into other programs and files, and it may infect them during that process. However, not all computer viruses are harmful. However, most of them perform intrinsically malicious operations such as data corruption. Some viruses may cause serious damage immediately after the code is executed, others may remain hibernate until certain events (such as programming) are started, and the code may be executed on the computer. When you transfer additional software or document from one computer to another using networks, disks, file sharing methods, or infected e-mail attachments, the virus spreads. Some viruses use different stealth strategies to prevent them from being detected from antivirus software. For example, some people can infect files without increasing the file size, others try to kill and avoid detection before detecting antivirus software related tasks. Some older viruses guarantee that the "last modified date" of the host file is the same when the file is infected.

In this complex environment, there is a computer virus. There is no exact and specific definition of computer viruses, but over time, several generally accepted facts relate to them. All viruses are programs or program fragments that reside in some form of memory. They are all created by someone who explicitly intends to become a virus. For example, an error (or error) in a program can be dangerous, but because it was incorrectly created by a software programmer, it is not considered a computer virus. Therefore, this virus is not accidentally generated. But they can sign and deliver by chance. In fact, one may even know that your computer may be infected with virus for several weeks. All viruses try to diffuse themselves in some way. Some viruses only copy their clones to the hard disk. These are called cloned viruses. They are highly destructive and can spread quickly and easily across the computer system.

In his thesis, Dr. Fred Cohen proposed a more accurate and scientific definition of the term "computer virus". This definition is mathematical - it defines a computer virus as a series of symbols on Turing machine 's tape. Although it is difficult to fully express this definition in human language, the approximate explanation is that computer viruses can be "infected by modifying other programs to include copies of their own possible evolution" That is to say. Unfortunately, there are some problems with this definition. One of them is not mentioning the possibility of a virus-infected program without changing it by inserting himself in the execution path. A typical example is the boot sector virus and its accompanying virus.