Which type of malware is often used to gain unauthorized access to a computer system?

Spyware is a type of malware specifically designed to observe and collect information from a computer system without the user's knowledge. This can include capturing keystrokes, browsing habits, and personal information, which can ultimately lead to unauthorized access to sensitive data or accounts. Spyware operates stealthily in the background, making it effective for malicious actors to exploit the information for nefarious purposes, such as identity theft or unauthorized system access.

In contrast, adware primarily focuses on delivering advertisements and often generates revenue for its creators through clicks or views, rather than seeking unauthorized access. Ransomware is designed to encrypt a user's files and demand a ransom for their release, which, while also malicious, typically doesn’t aim to collect information covertly. Utility software, on the other hand, is created to help manage, maintain, or control computer resources and does not fit the malware category or its intent to gain unauthorized access.