what is a computer worm

A computer worm is a type of malware that can self-replicate and spread from one computer to another without human intervention after breaching a system. It often uses a computer network to spread itself, relying on security failures on the target computer to access it. Worms can spread through email attachments, instant messages, spam emails, and software vulnerabilities. Once a worm has breached a computers defenses, it can perform several malicious actions, such as dropping other malware, consuming bandwidth, deleting files, overloading networks, stealing data, and opening a backdoor. Worms can modify and delete files, and they can even inject additional malicious software onto a computer. Sometimes a worms purpose is only to make copies of itself over and over, depleting system resources, such as hard drive space or bandwidth, by overloading a shared network. Worms can also steal data, install a backdoor, and allow a hacker to gain control over a computer and its system settings.