What is the best definition of malware in the context of cyber security?

The definition that describes malware most accurately in the context of cyber security is that it is malicious software designed to harm, exploit, or compromise systems. Malware encompasses a wide range of harmful software types, including viruses, worms, Trojans, ransomware, and spyware. The key characteristics of malware are its intent to damage or unauthorizedly access devices, systems, networks, or data. This definition highlights both the maliciousness and the objective of such software—to create vulnerabilities or enact harm, making it a critical concern for cyber security professionals focused on protecting systems and data from such threats.

Other definitions do not capture the essence of malware. For instance, software intended to improve system performance or programs that facilitate authorized access do not align with malware's inherently harmful purpose. Similarly, security software designed to protect against unauthorized access is the opposite of malware, since it is intended to safeguard systems rather than compromise them. Thus, option B encapsulates the core understanding of what malware is in cyber security.