The way a virus or rogue program spreads to other computers varies with the type
A program virus becomes active when a program infected with a
virus is run. Once a program virus is active, it will usually
infect other programs on the computer. If a copy of an infected
program is moved to and run on another computer, it can then
infect programs on that computer.
A boot sector virus infects hard disks and diskettes. If a
computer is re-booted or its power is turned on while an
infected diskette is in its disk drive, the virus will spread to the
hard disk, even if the diskette is not capable of starting up
the computer. Once the hard disk is infected, all diskettes used
in the computer will be infected and can spread the infection to
A macro virus becomes active when a document infected with the
virus is opened using the program it is designed to attack. The
program must have its ability to run macros enabled (turned on).
Generally, when a virus in a document becomes active, it will
spread to global settings for the application so that other
documents will become infected when they are opened. When an
infected document is opened on another computer, the global
settings used by that copy of the application will be infected
An e-mail virus spreads through e-mail messages and usually
replicates by automatically mailing itself to all entries in the
victim's e-mail address book.
A worm replicates itself using
existing security holes on systems attached to a network. It
scans the network for
for computer that will let it exploit the security hole to infect
them. Then, from the newly-infected computers, it continues to
probe the network for other vulnerable systems.
A Trojan horse cannot usually replicate itself. However,
it, too, can still damage your computer.
Subscribe to our newsletter to get the latest news, updates and offers.
We are a small team of developers who love to create awesome websites. This website is a place where you can find all the answers to your questions. All the questions are posted by the users and the answers are posted by the experts.