On which factor should an IS auditor primarily focus for determining the appropriate level of protection for an information asset?

The appropriate level of protection for an information asset should primarily be determined by the results of a risk assessment. Risk assessments evaluate various factors, including potential threats, vulnerabilities, and the impact of different types of risks on the organization. By understanding the likelihood and potential consequences of each risk, an IS auditor can identify which information assets require higher levels of protection and which may have acceptable levels of risk.

Ultimately, a risk assessment allows for a comprehensive evaluation of the vulnerabilities associated with information assets and the potential business implications of those risks. This process helps ensure that security measures are aligned with the actual risk profile faced by the organization, leading to more effective allocation of resources and better protection strategies.

Whereas cost of security controls may be a consideration in implementing security measures, it does not provide a complete picture of what level of protection is necessary. Similarly, while the results of a vulnerability assessment identify weaknesses in the system, they do not address the full context of potential threats and impacts. The relative value to the business is important in prioritizing security initiatives, but without a risk assessment, those priorities may not align with actual risk exposure. Thus, focusing on risk assessment establishes a more informed basis for determining protection levels.