UNSW Sydney · FACULTY OF FINANCE

RISK5002 Chap.8 Cyber Risk, Privacy Impact and Monte Carlo

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Chapter 8 of 10 · RISK5002

Cyber Risk, Privacy Impact and Monte Carlo

Cyber risk is not named in ISO 31000 or IEC 31010, but the course treats it with the same principles: identify the most valuable digital assets, test leadership commitment and accountability, check that a systematic process links to enterprise risk management, define the cyber risk the organisation will accept, and make communication and consultation work across cyber, legal and operations.

Data protection impact analysis examines how incidents could affect personal data and prioritises processes, services and scenarios. Monte Carlo simulation samples input distributions to build the distribution of loss. This chapter traces a ransomware simulation by hand, compares results before and after controls, and reviews health checks, red teaming and breach and attack simulation.

The lecture's ransomware model combines a yearly chance of an incident with a heavy-tailed loss, then asks how controls change the average loss, the high percentiles and the chance of a loss above one million dollars. The chapter reproduces that logic with ten hand-worked years so the mechanics are visible, then explains why such a small run cannot support a decision.

It closes with the testing tools that sit outside the standards, from a free health check to red teams and automated attack simulation.

In this chapter

What this chapter covers

  • 01

    ISO 31000 questions for cyber risk

  • 02

    Data protection impact analysis

  • 03

    Monte Carlo simulation steps

  • 04

    Simulating loss before and after controls

  • 05

    Why small simulations mislead

  • 06

    Red teaming and attack simulation

Worked example · free

Ten simulated years of ransomware loss

Q [4 marks]. An incident occurs in a year if a uniform draw is below 0.25. The ten draws are 0.62, 0.08, 0.91, 0.33, 0.19, 0.77, 0.45, 0.03, 0.58 and 0.86, and incident losses are $85,000, $240,000 and $1,150,000 in order. Controls halve the threshold to 0.125 and cap losses at $300,000. Compare mean annual loss. The mark allocation is our own practice weighting and not an official university scheme.
Ten simulated years of ransomware loss using the same random draws before and after controls: incidents fall from three years to two, the worst year is capped aTen simulated years of ransomware loss using the same random draws before and after controls: incidents fall from three years to two, the worst year is capped at $300k instead of $1.15m, and the mean annual loss drops from $147,500 to $38,500.Mean $147,500Mean $38,500$1.15m$300k$240kBefore controlsAfter controlsSimulated years 1 to 10
Ten simulated years of ransomware loss using the same random draws before and after controls: incidents fall from three years to two, the worst year is capped at $300k instead of $1.15m, and the mean annual loss drops from $147,500 to $38,500.
  • +1Before: incidents in years 2, 5 and 8 total $1,475,000, a mean of $147,500 a year.
  • +1After: only years 2 and 8 fall below 0.125, and the cap turns $1,150,000 into $300,000.
  • +1After total $385,000, a mean of $38,500 a year: a fall of $109,000.
  • +1Ten iterations show the mechanics only; thousands are needed before reading percentiles.
Mean annual loss falls from $147,500 to $38,500, but ten runs are far too few for a decision. The fall shows the combined effect of a lower incident probability and a capped loss per incident.
Sia tip — Reuse the same random draws for both scenarios so the difference reflects the controls rather than chance.
Glossary

Key terms

Privacy impact analysis
A study of how incidents could affect personal data and the capabilities needed in response.
Red teaming
A permitted, simulated cyberattack by ethical hackers to expose vulnerabilities.
Iteration
One sampled run of a simulation model producing a single output value.
Breach and attack simulation
Automated, continuous testing that mimics real attack tactics.
FAQ

Cyber Risk, Privacy Impact and Monte Carlo FAQ

How does ISO 31000 apply to cyber risk?

Treat cyber risk like any other risk: link it to objectives and key digital assets, secure board commitment and clear accountability, integrate it into the enterprise process, set criteria for acceptable cyber risk, and make communication and consultation bring cyber, legal and operations experts together with risk owners.

What does a data protection impact analysis produce?

It produces prioritised lists of critical information processes and of the products and services involved, scenarios where processing personal data is high risk, and outage time frames for containment and recovery.

Why can Monte Carlo results give false confidence?

Accuracy depends on how many iterations are run, and rare high-consequence events may never be sampled, so the tail of the distribution can look safer than it is. Report the number of runs and treat extreme percentiles cautiously.

How do controls show up in a Monte Carlo cyber model?

Controls change the input distributions. Multi-factor authentication and system hardening lower the probability that an incident occurs in a year, while tested backups limit the loss from each incident. Running the simulation with the same random draws before and after the change isolates the effect of the controls on the distribution of annual loss.

Study strategy

Exam move

Turn each ISO element into one cyber question for a business you know, so you can generate the list in an exam. Learn the DPIA inputs and outputs as two short lists. For simulation, repeat the hand exercise with new draws, compute the mean and an exceedance estimate, and explain in one sentence why more iterations are needed. Close by comparing red teaming with automated attack simulation.

When you revise testing tools, write one sentence each on depth, frequency and cost for a health check, a red team and breach and attack simulation, so a recommendation question can be answered with a justified mix.

Working through Cyber Risk, Privacy Impact and Monte Carlo in RISK5002? Sia is AskSia’s AI Finance tutor — ask any RISK5002 Cyber Risk, Privacy Impact and Monte Carlo question and get a clear, step-by-step explanation grounded in how RISK5002 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.

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