Which type of malware is designed to replicate itself and spread to other machines?

The type of malware designed to replicate itself and spread to other machines is a worm. Unlike other forms of malware, worms are capable of self-replication, meaning they can create copies of themselves and spread independently across networks without the need for human intervention or a host file, unlike viruses. This characteristic allows worms to proliferate quickly, potentially causing significant harm by consuming bandwidth, exploiting vulnerabilities, and disrupting system performance.

In contrast, phishing is primarily a social engineering tactic that deceives individuals into providing sensitive information, while a Trojan horse disguises itself as legitimate software but performs malicious actions once installed. Spyware focuses on collecting user information without their consent, often for purposes such as tracking behaviors or stealing data. Worms specifically target the ability to replicate and spread, making them distinct from these other malware types.