A computer virus is small piece of code usually hidden inside another computer program. It is also referred to as a malware program or a malicious program because it is capable of partly or entirely disrupting a computer’s operations.
The same technology used to create legitimate software is the same that is used to create computer viruses. The difference is that a computer virus has the ability to replicate and embed copies into other computer programs. Viruses are described as self-replicating computer programs. They tend to install themselves without the user’s permission, and they usually hide themselves. Affected programs or files are said to be infected.
Computer viruses can be found embedded in downloaded programs and CDs. They spread through removable storage devices, computer networks, wireless communication channels and point-to-point communication systems. They do these primarily through file execution, file transfer and file copy.
They are used for harmful activities such as corrupting data, gaining access to private information, spamming contacts, deleting files, and stealing computer storage, memory and processing time. Computer virus infections can lead to entire systems failure, wastage of computer resources and increased maintenance costs.
Examples of computer viruses include worms, Trojan horses and logic bombs. While some viruses are intended to cause harm, others are used as pranks and are not intended to cause harm.