A computer virus is a type of malicious computer program or malware that replicates itself when executed by modifying other computer programs and inserting its own code. Computer viruses generally require a host program to be able to write its own code into. This is in contrast to a computer worm.
Computer viruses are deliberately written by programmers who use various methods to distribute the program such as social engineering, deceptive downloads. The programs tend to exploit security vulnerabilities in the host program or system in order to successfully infect a user’s computer.
Computer viruses can be countered using anti-virus programs.