What type of malware is known for collecting user information without their consent?

Spyware is a type of malware specifically designed to collect user information without their knowledge or consent. This can include tracking user activity, capturing keystrokes, or scanning files for sensitive data such as passwords and credit card numbers. The key characteristic of spyware is its stealthy operation; it often runs in the background without the user's awareness, making it particularly dangerous as users may unknowingly compromise their privacy and security.

In contrast, adware primarily focuses on serving advertisements to users, often in a manner that can be intrusive but not necessarily secretive in terms of personal data collection. Worms are self-replicating malicious programs that can spread across networks but do not typically engage in collecting user-specific information. Ransomware encrypts the victim's files and demands payment for their release, rather than focusing on data collection. Therefore, spyware is distinct for its primary goal of harvesting personal information covertly.