A computer worm is a type of malware that infects a computer, replicates and spreads to other computers.
Worms are programmed to use computer networks to send copies of themselves to other computers, meaning that they do not require a cyber criminal’s guidance to spread.
A common function of a worm is to install a ‘backdoor’ on the computer, allowing the worm author to take control of it.
A worm will typically use a computer network in order to spread itself and relies upon security failings in order to access it.