CyberStack

Glossary / concepts acsc-glossary

Availability

Authorised users can actually use the system when the work needs it. Uptime theatre without backups is a bet.

CIA triadThe CIA triad: Confidentiality, Integrity, and Availability. Three properties of information security, not a slogan. Lose one and the system is already failing even if the dashboard is green.ANDANDCConfidentialityauthorised eyes onlyIIntegritywritten by the right handAAvailabilitythere when work needs itCIA TRIAD / THREE PROPERTIESLose one pillar and the system is already failing.Check every control against all three — or it is decoration.

Availability is the assurance that systems stay reachable and usable for the people and processes allowed to use them. Capacity, redundancy, patching that does not brick the fleet, and restores you have practised all sit here.

Denial-of-service is the loud failure. The quiet ones are expired certificates, a single cloud region, and backups that restore into a smoking crater.

Do not trade it away for confidentiality theatre. A locked vault nobody can open during an incident is an outage with better branding.

Fact source: ASD's ACSC glossary.