Which of the following is NOT a common type of malware?

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

Answer: (D)

The choice of "Router" is correct as it is not a type of malware. A router is a network device that manages traffic between different networks, particularly on the internet. It directs data packets between devices and plays a crucial role in network operations.

In contrast, a virus, worm, and Trojan are all types of malware. A virus attaches itself to legitimate files and programs, spreading when those files are shared or executed. A worm is a type of malware that replicates itself to spread to other systems without needing to attach to a host file. A Trojan disguises itself as a legitimate application, tricking users into downloading and executing it, allowing unauthorized access to the user's system.

Understanding these distinctions is vital for recognizing the different threats posed by malware and their operational characteristics in the context of network security.