What characteristic distinguishes a computer virus from a worm?

The characteristic that distinguishes a computer virus from a worm is the method of propagation and how they replicate. A worm is classified as self-propagating malware that can spread independently across networks by exploiting vulnerabilities without needing to attach itself to a host file. It actively seeks out other systems to infect, often using external means of transport such as network connections and email.

In contrast, a computer virus requires a host file to spread. It attaches itself to legitimate programs or files and relies on user action, such as running the infected program, to enable the virus to propagate.

This fundamental difference in how they spread is crucial in understanding the behavior of these types of malware. Worms can replicate and spread more rapidly than viruses, making them particularly dangerous in network environments.