Which type of malware does not require the user to execute any action to spread?

The type of malware that does not require the user to execute any action to spread is a worm. Unlike viruses that attach themselves to host files or require some form of user action to activate and propagate, worms are specifically designed to replicate and spread independently over networks. They exploit vulnerabilities in operating systems or applications to infect other systems without any user intervention.

Worms often spread through networks, utilizing protocols to replicate themselves onto other machines, which allows them to quickly proliferate across connected devices. This ability to self-replicate and autonomously spread makes worms particularly dangerous and effective at infiltrating large networks.

On the other hand, other types of malware, such as trojan horses, require users to execute a program or open a file, while viruses need a host program to attach to and rely on user actions to initiate replication. Spyware, while potentially capable of spreading on its own, is primarily designed to gather information and usually requires some level of user consent to install. Thus, worms stand out as the category of malware that operates without the user's direct involvement in its spread.