Which type of malware spreads without injecting into a host program and usually does not require human interaction?

The correct answer is that the computer worm is a type of malware that spreads independently and typically does not require human interaction to propagate. Unlike other forms of malware such as viruses, which need to attach themselves to a host file in order to spread, worms are standalone programs that exploit vulnerabilities in networks or systems to replicate themselves. This ability allows them to move across networks without direct user engagement, relying on flaws or security holes in operating systems or applications to proliferate.

In contrast, a computer virus requires a host file to attach itself to and cannot spread on its own. Ransomware typically demands action from users, such as payment, to unlock files, and it often utilizes other methods to spread rather than self-replicating. Trojan horses disguise themselves as legitimate software but cannot self-replicate like worms; they require users to unknowingly execute them to initiate their malicious activity. Therefore, the characteristic nature of worms distinguishes them as the type of malware that spreads without needing a host program and usually operates without human involvement.