A computer virus is a
computer program that can copy ഇറ്സെല്ഫ് and infect a computer. The term "virus" is also commonly but erroneously used to refer to other types of
malware, including but not limited to
adware and
spyware programs that do not have the reproductive ability. A true virus can spread from one computer to another (in some form of executable
code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a
floppy disk,
CD,
DVD, or
USB drive.
[2] Viruses can increase their chances of spreading to other computers by infecting files on a
network file system or a file system that is accessed by another computer.
[3]As stated above, the term "computer virus" is sometimes used as a catch-all phrase to include all types of
malware, even those that do not have the reproductive ability. Malware includes computer viruses,
computer worms,
Trojan horses, most
rootkits,
spyware, dishonest
adware and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with worms and Trojan horses, which are technically different. A worm can exploit security
vulnerabilities to spread itself automatically to other computers through networks, while a Trojan horse is a program that appears harmless but hides malicious functions. Worms and Trojan horses, like viruses, may harm a computer system's data or performance. Some viruses and other malware have symptoms noticeable to the computer user, but many are surreptitious or simply do nothing to call attention to themselves. Some viruses do nothing beyond reproducing themselves