ISC2 Certified in Cybersecurity (CC)Security PrinciplesMedium

A critical infrastructure organization manages a Supervisory Control and Data Acquisition (SCADA) system. They have determined that a single outage event on a specific control server could lead to a loss of $50,000. Historical data indicates that this type of outage occurs approximately once every two years. What is the Annualized Loss Expectancy (ALE) for this specific risk?

  1. A$25,000
  2. B$100,000
  3. C$50,000
  4. D$125,000
Show answer & explanation

Correct answer: A. $25,000

The Annualized Loss Expectancy (ALE) is calculated by multiplying the Single Loss Expectancy (SLE) by the Annualized Rate of Occurrence (ARO). In this case, SLE = $50,000 and ARO = 0.5 (1 occurrence / 2 years). So, ALE = $50,000 * 0.5 = $25,000.

Why the other options are wrong

  • B. This would be the ALE if the event occurred twice a year (50,000 * 2), which is incorrect.
  • C. This is the Single Loss Expectancy (SLE), not the Annualized Loss Expectancy (ALE).
  • D. This calculation is incorrect for the given values.

Annualized Loss Expectancy (ALE)

The estimated financial loss from a specific risk over a one-year period. It quantifies risk in monetary terms.

  • Calculated as SLE * ARO.
  • Helps prioritize risk mitigation efforts.
  • Expressed in monetary value per year.

Memory trick: ALE is the total loss you'd expect to feel, annually.

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