Which concept describes a malware program that masquerades as legitimate software?

• A. Trojan Horse
• B. Virus
• C. Worm
• D. Adware

Answer: (A)

The concept here is deception through concealment inside something that looks legitimate. A Trojan Horse hides its malicious payload inside a program that appears useful or trustworthy, so users are tricked into running it. Once activated, it can perform harmful actions like opening a backdoor, stealing data, or installing additional malware, all while the user believes they’ve installed ordinary software.

This differs from a virus, which attaches itself to other files and relies on replication to spread; a worm, which self-propagates across networks without user action; and adware, which primarily displays advertisements and isn’t defined by hiding malicious functionality inside a legitimate program. The defining feature of a Trojan is that it deceives by masquerading as something benign to gain execution.