How does a worm typically propagate?

Worms propagate primarily through email and other network connections because they are designed to replicate themselves across networks without human intervention. This self-replicating nature allows worms to spread rapidly, often exploiting vulnerabilities in software or operating systems to infect a machine and then use that machine to reach other connected systems.

For instance, when a worm infects a host, it can scan for other IP addresses on the network, sending copies of itself to those addresses. This can happen without any user action, making worms particularly dangerous as they can spread widely and quickly within networked environments.

In contrast, methods such as using USB drives are more characteristic of other malware types, while infecting files is specific to viruses. Manually installing software relies on user action, which is not how worms operate. Hence, the method of propagation via email and network connections is fundamentally what distinguishes worms from other types of malware.