What type of malware is disguised as harmless software but performs malicious functions?

The type of malware that is disguised as harmless software but performs malicious functions is a Trojan. Trojans masquerade as legitimate applications or files to trick users into downloading or executing them. Once installed, they can perform a variety of harmful activities, such as stealing personal data, creating backdoors for further attacks, or enabling other types of malware to be installed on the system.

Trojans do not replicate themselves like viruses, making them distinct in their method of operation. They rely heavily on social engineering tactics to entice users into thinking they are safe. This is why recognizing Trojans is crucial for maintaining security, as users often unwittingly create vulnerabilities simply by interacting with what they believe to be safe software.

In contrast, other types of malware serve different purposes: spyware secretly monitors user activity, ransomware encrypts files and demands payment for their release, and adware displays unwanted advertisements and can slow down system performance but typically does not have malicious intent in the way that Trojans do. Understanding the nature and behavior of these different types of malware is key in implementing effective security measures.