A retailer's e-commerce site is hit with a volumetric DDoS attack during a holiday sale, taking checkout offline for two hours. Which leg of the CIA triad was PRIMARILY violated?

Sources

1. [1]NIST SP 800-12 Rev. 1, An Introduction to Information Security, Section 1.4, Important Terminology
2. [2]NIST SP 800-12 Rev. 1, An Introduction to Information Security, Appendix B, Glossary (Denial of Service)
3. [3]ISC2 CISSP Certification Exam Outline, Domain 1