Availability
Definition
The property that systems and data are accessible to authorised users when needed. Protected by redundancy, backup, failover, and incident response capabilities. Breached by denial-of-service attacks, hardware failure, or ransomware.
- Pillar of
- The CIA triad
- Protected by
- Redundancy, backup, failover
- Threatened by
- Denial-of-service, ransomware, hardware failure
Common questions
How does ransomware attack availability specifically, as distinct from confidentiality?+
Ransomware encrypts data so authorized users can no longer access it, without necessarily exposing or exfiltrating the content, making it primarily an availability attack even though some variants also threaten confidentiality.
What is the difference between availability as a security property and business continuity planning?+
Availability is the specific property that data and systems stay accessible when needed. Business continuity planning is the broader organizational process, including procedures and staffing, that helps achieve that property.
Related terms
- Confidentiality
- The property that information is not disclosed to unauthorised individuals, processes, or devices. Protected by access controls, encryption, and need-to-know policies. Breached...
- Integrity
- The property that information is accurate, complete, and has not been modified without authorisation. Protected by cryptographic hashing, digital signatures, and change...
- Non-Repudiation
- The property that a party cannot deny having performed an action. Provided by digital signatures, timestamped audit logs, and certified delivery receipts....
- Threat
- A potential cause of an unwanted incident that could harm an asset. Threats may be natural (flood, fire), environmental (power failure), human...
- Vulnerability
- A weakness in an asset or in a control protecting that asset, which a threat could exploit to cause harm. Examples: an...