Which type of malware self-propagates without user interaction and spreads through a network?

• A. Trojan
• B. Worm
• C. Virus
• D. Spyware

Answer: (B)

The idea being tested is self-propagation across a network. A worm is designed to copy itself to other machines and spread without any user action, by scanning for vulnerable hosts and exploiting weaknesses or using weak credentials to move laterally. This autonomous spreading is what sets worms apart from other malware.

In contrast, a Trojan hides inside something that appears legitimate but must be executed by the user or opened by them to run. A virus attaches to a host file and typically requires the user to run or trigger the infected program to spread. Spyware focuses on covertly gathering information from a system rather than propagating to other machines.