Final answer:
Total risk is defined as the product of a threat, vulnerability, and asset value, which represents a more comprehensive measure of potential impact in risk management, often prompting conservative mitigation strategies.
Step-by-step explanation:
The proper definition of total risk in the context of threats and mitigation, especially in an information security framework, is Threat x Vulnerability x Asset Value. This model quantifies risk by considering the nature of the threat, how exploitable the vulnerability is, and how valuable the asset in question is. It's not merely a matter of subtracting mitigation efforts or controls from threats or vulnerabilities; rather, it's about understanding the potential impact in a multiplicative sense, to get a more accurate picture of what's at stake. In scenarios where the risk is asymmetric, it is paramount to consider the severe consequences of inaction (Plan A) versus the costs associated with preventive actions (Plan B), even if the former offers a more 'natural' course of action when the threat doesn't appear to be imminent. As illustrated in Figure 20.1, facing potentially catastrophic threats requires a conservative approach by formulating mitigation plans, similar to buying insurance for low-probability, high-impact events.