1. What is Residual Risk in RMF?

Residual risk is the risk remaining after security controls have been applied to mitigate inherent risks. In the Risk Management Framework (RMF), it represents the portion of risk that remains after implementing security measures.

2. How Does the Calculator Work?

The calculator uses the residual risk formula:

Where:

• Inherent Risk — The risk level before any security controls are applied (unitless)
• Mitigation Impact — The reduction in risk achieved by security controls (unitless)
• Residual Risk — The remaining risk after controls are applied (unitless)

Explanation: This simple formula helps quantify how much risk remains after implementing security measures in the RMF process.

3. Importance of Residual Risk Calculation

Details: Calculating residual risk is crucial for determining whether additional controls are needed and for making risk acceptance decisions in the RMF process.

4. Using the Calculator

Tips: Enter the inherent risk value (before controls) and the mitigation impact value (how much risk reduction was achieved). Both values should be on the same scale (typically 0-10 or 0-100).

5. Frequently Asked Questions (FAQ)

Q1: What scale should I use for risk values?
A: You can use any consistent scale (e.g., 0-10, 0-100) as long as both inherent risk and mitigation impact use the same scale.

Q2: What if residual risk is negative?
A: Negative values suggest the mitigation impact exceeds the inherent risk, which may indicate over-mitigation or measurement errors.

Q3: How is mitigation impact determined?
A: Mitigation impact is typically estimated based on the effectiveness of implemented security controls.

Q4: What's an acceptable residual risk level?
A: Acceptable levels vary by organization and should be defined in your risk management policy.

Q5: Does this account for all risk factors?
A: This is a simplified calculation. Comprehensive RMF analysis should consider additional factors like likelihood and impact.