How can malware affect a computer system?

Malware can have a significant and harmful impact on a computer system, primarily by disrupting its normal operations and compromising the privacy and integrity of data. Specifically, malware is designed to perform malicious actions such as deleting files, corrupting data, or taking control of system processes. Furthermore, many types of malware, such as viruses, worms, and ransomware, are explicitly built to gain unauthorized access to sensitive information, leading to data breaches or identity theft.

In contrast, the other options suggest positive outcomes that are not characteristic of malware's functionality. Improving system performance, installing updates automatically, and enhancing data security measures are all beneficial actions typically associated with legitimate software rather than malicious programs. Therefore, the main characteristic of malware is its ability to cause harm by disrupting normal operations and stealing information, which clearly aligns with the identified choice.