Security metrics, SLOs and risk quantification

Metrics that change decisions: time to remediate by tier, MFA coverage, detection precision, and how to put a number on risk without pretending to be precise.

🔒 PROLesson·20 min read·Advanced → Staff
metricsSLOriskleadership

01Metrics that change decisions

✓What you will learn
  • Pick leading and lagging indicators that leadership will act on
  • Set security SLOs with error budgets
  • Explain FAIR-style risk ranges without false precision
MetricTypeWhy it moves decisions
% workloads on workload identity (no static keys)LeadingDirectly shrinks credential theft impact
Phishing-resistant MFA coverageLeadingRemoves the top initial access vector
Critical vuln MTTR, internet-facingLaggingSLA burn makes prioritisation explicit
Detection precision per ruleQualityLow precision is analyst burnout
Mean time to containLaggingMeasures response engineering, not luck
▭On the whiteboard · Security SLOs3 points
01
patch
99% of internet-facing criticals fixed < 7 d
02
identity
100% of prod access via SSO + hardware MFA
03
detect
p95 time from event to alert < 5 min for tier-1 sources

For risk, resist a single number. Give a range with assumptions: "a leaked customer-data export is plausible once every 2 to 5 years given current controls; impact 2 to 10 M in notification, churn and fines. Control X moves likelihood to once per 10 to 20 years for Y cost." Leaders can compare that to other spend. A heat map cannot be compared to anything.

“How to say it in the room

"I pick a handful of metrics that are both measurable and causal: identity coverage, time to fix exposed criticals, detection precision, time to contain. Then I set SLOs and report the budget burn, so security competes for priority with the same vocabulary as reliability."

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