sentence: Worms spread over networks, or on removable media like USB flash drives.
sentences_before: A 'computer worm' is a kind of malware that is able to copy itself, and spread. Unlike a computer virus, this is done without changing files on a computer, and without affecting the boot sector of media.
sentences_after: They almost always need a helper program that is able to access the network, or that executes when a new medium is inserted.
concept_name: worm
headings: Computer worm
categories: Malware