What type of malware disguises itself as legitimate software?

A Trojan horse is a type of malware that disguises itself as legitimate software to trick users into installing it. Unlike other forms of malware that may act maliciously immediately upon the user's interaction, a Trojan often appears harmless or beneficial, such as a useful application or game. Once activated, however, it can perform unwanted actions, such as stealing data, creating backdoors, or allowing remote access to attackers.

This behavior is particularly dangerous because users may unwittingly introduce the malware into their systems, believing it to be a trustworthy application. By presenting itself in a way that mimics legitimate software, a Trojan horse exploits human trust, effectively bypassing some of the security measures that users might employ against more obviously harmful applications.

In contrast, adware typically serves advertisements and can slow down systems, while spyware is designed specifically to gather information without the user’s knowledge. Rootkits, on the other hand, aim to gain unauthorized access to systems and maintain control over them, often hiding their presence from the user. None of these types of malware are specifically designed to imitate legitimate software in the same way that Trojans do.