Which malware type is primarily aimed at providing unauthorized access to systems?

The chosen answer, which identifies backdoor malware as primarily aimed at providing unauthorized access to systems, is accurate because backdoors are specifically designed to allow attackers to bypass normal authentication and gain access to systems without going through standard security measures. This form of malware often remains hidden within legitimate software, enabling the attacker to exploit the system at any time without detection.

Backdoors may be installed after an initial compromise, allowing the attacker ongoing access, or they can be put in place by developers for various reasons, including the ability to maintain control over a system remotely. The purpose of backdoor malware distinctly aligns with the intent to facilitate unauthorized access.

In contrast, the other types of malware, such as worms, viruses, and Trojan horses, serve different primary functions. Worms typically self-replicate and spread across networks, exploiting vulnerabilities but not necessarily focused on unauthorized access alone. Viruses attach themselves to clean files and spread to other files, often damaging data. Trojan horses deceive users into installing them by masquerading as legitimate software, but their primary function often revolves around actions like data theft or system compromise rather than establishing unauthorized access per se. This delineation highlights why backdoor malware is the most direct answer to the question regarding unauthorized access.