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could cause damage, destruction, alteration, loss, or disclosure of assets or that could block access to or prevent maintenance of assets. They can be intentional or accidental. They can originate from inside or outside. You can loosely think of a threat as a weapon that could cause harm to a target.

       Threat Agent/Actors Threat agents or threat actors intentionally exploit vulnerabilities. Threat agents are usually people, but they could also be programs, hardware, or systems. Threat agents wield threats in order to cause harm to targets.

       Threat Events Threat events are accidental occurrences and intentional exploitations of vulnerabilities. They can also be natural or person-made. Threat events include fire, earthquake, flood, system failure, human error (due to a lack of training or ignorance), and power outage.

       Threat Vector A threat vector or attack vector is the path or means by which an attack or attacker can gain access to a target in order to cause harm. Threat vectors can include email, web surfing, external drives, Wi-Fi networks, physical access, mobile devices, cloud, social media, supply chain, removable media, and commercial software.

       Vulnerability The weakness in an asset or the absence or the weakness of a safeguard or countermeasure is a vulnerability. In other words, a vulnerability is a flaw, loophole, oversight, error, limitation, frailty, or susceptibility that enables a threat to cause harm.

       Exposure Exposure is being susceptible to asset loss because of a threat; there is the possibility that a vulnerability can or will be exploited by a threat agent or event. Exposure doesn't mean that a realized threat (an event that results in loss) is actually occurring, just that there is the potential for harm to occur. The quantitative risk analysis value of exposure factor (EF) is derived from this concept.

       Risk Risk is the possibility or likelihood that a threat will exploit a vulnerability to cause harm to an asset and the severity of damage that could result. The more likely it is that a threat event will occur, the greater the risk. The greater the amount of harm that could result if a threat is realized, the greater the risk. Every instance of exposure is a risk. When written as a conceptual formula, risk can be defined as follows:risk = threat * vulnerabilityorrisk = probability of harm * severity of harm

      Thus, addressing either the threat or threat agent or the vulnerability directly results in a reduction in risk. This activity is known as risk reduction or risk mitigation, which is the overall goal of risk management.

      When a risk is realized, a threat agent, a threat actor, or a threat event has taken advantage of a vulnerability and caused harm to or disclosure of one or more assets. The whole purpose of security is to prevent risks from becoming realized by removing vulnerabilities and blocking threat agents and threat events from jeopardizing assets.

       Safeguards A safeguard, security control, protection mechanism, or countermeasure is anything that removes or reduces a vulnerability or protects against one or more specific threats. This concept is also known as a risk response. A safeguard is any action or product that reduces risk through the elimination or lessening of a threat or a vulnerability. Safeguards are the means by which risk is mitigated or resolved. It is important to remember that a safeguard need not involve the purchase of a new product; reconfiguring existing elements and even removing elements from the infrastructure are also valid safeguards or risk responses.

       Attack An attack is the intentional attempted exploitation of a vulnerability by a threat agent to cause damage, loss, or disclosure of assets. An attack can also be viewed as any violation or failure to adhere to an organization's security policy. A malicious event does not need to succeed in violating security to be considered an attack.

       Breach A breach, intrusion, or penetration is the occurrence of a security mechanism being bypassed or thwarted by a threat agent. A breach is a successful attack.

Some of these risk terms and elements are clearly related, as shown in Figure 2.2. Threats exploit vulnerabilities, which results in exposure. Exposure is risk, and risk is mitigated by safeguards. Safeguards protect assets that are endangered by threats.

There are many approaches to risk assessment. Some are initiated by evaluating threats, whereas others focus first on assets. Whether a risk assessment starts with inventorying threats, then looks for assets that could be harmed, or starts with inventorying assets, then looks for threats that could cause harm, both approaches result in asset-threat pairings that then need to be risk evaluated. Both approaches have merit, and organizations should shift or alternate their risk assessment processes between these methods. When focusing first on threats, a broader range of harmful issues may be considered, without being limited to the context of the assets. But this may result in the collection of information about threats that the organization does not need to worry about as they don't have the assets or vulnerabilities that the threat focuses on. When focusing first on assets, the entirety of organizational resources can be discovered without being limited to the context of the threat list. But this may result in spending time evaluating assets of very low value and low risk (which would or will be defined as acceptable risk), which may increase the overall time involved in risk assessment.

FIGURE 2.2 The cyclical relationships of risk elements

      The general idea of a threat-based risk assessment was discussed in Chapter 1. The discussion of risk assessment in this chapter will focus on an asset-based risk assessment approach.

      Asset Valuation

      An asset-based or asset-initiated risk analysis starts with inventorying all organizational assets. Once that inventory is complete, a valuation needs to be assigned to each asset. The evaluation or appraisal of each asset helps establish its importance or criticality to the business operations. If an asset has no value, there is no need to provide protection for it. A primary goal of risk analysis is to ensure that only cost-effective safeguards are deployed. It makes no sense to spend $100,000 protecting an asset that is worth only $1,000. Therefore, the value of an asset directly affects and guides the level of safeguards and security deployed to protect it. As a rule, the annual costs of safeguards should not exceed the potential annual cost of asset value loss.

When the cost of an asset is evaluated, there are many aspects to consider. The goal of asset valuation is to assign to an asset a specific dollar value that encompasses tangible costs as well as intangible ones. Determining an exact value of an asset is often difficult if not impossible, but nevertheless, a specific value must be established in order to perform quantitative mathematical calculations. (Note that the discussion of qualitative versus quantitative risk analysis later in this chapter may clarify this issue; see the “Risk Assessment/Analysis” section.) Improperly assigning value to assets can result in failing to properly protect an asset or implementing financially infeasible safeguards. The following list includes tangible and intangible issues that contribute to the valuation of assets:

       Purchase cost

       Development cost

       Administrative or management cost

       Maintenance or upkeep cost

       Cost in acquiring asset

       Cost to protect or sustain asset

       Value to owners and users

       Value to competitors

       Intellectual property or equity value

       Market valuation (sustainable price)

       Replacement cost

       Productivity enhancement or degradation

       Operational

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