What is malware designed to do?

Malware is specifically designed to harm, exploit, or compromise a computer system. This can include various harmful actions such as stealing sensitive information, corrupting data, or taking control of systems to carry out unwanted tasks. Unlike legitimate software that is developed to provide useful features and enhance the performance of systems, malware operates with malicious intent.

The other options do not align with the purpose of malware. Enhancing computer functionality and increasing network speed represent positive enhancements to a system, while protecting against unauthorized access refers to security measures, not harmful software. Thus, focusing on the malicious nature of malware, option B captures its true design and intent.