SOC 2 vs CSA STAR: attestation and the cloud security registry
CSA STAR is not a competitor to SOC 2 so much as a cloud-specific layer that can build on top of it, including a Level 2 attestation that maps SOC 2 to the Cloud Controls Matrix.
Different bodies, overlapping goals
SOC 2 is an AICPA attestation framework, delivered by CPA firms reporting against the Trust Services Criteria, with Security mandatory and the other four categories scoped in as needed. CSA STAR (Security, Trust, Assurance and Risk) is a program run by the Cloud Security Alliance, built around the Cloud Controls Matrix (CCM) and its companion questionnaire, the Consensus Assessments Initiative Questionnaire (CAIQ). The CCM is a control framework purpose-built for cloud computing, with hundreds of controls mapped to standards including ISO 27001 and the CIS Controls. Where SOC 2 produces a confidential report a customer requests under NDA, STAR centers on a public registry where cloud providers publish their assurance posture for prospective buyers to browse.
The two STAR levels
STAR Level 1 is a self-assessment: a provider completes the CAIQ against the Cloud Controls Matrix and publishes it to the public STAR Registry, making it a low-cost, low-friction transparency signal suited to lower-risk environments. STAR Level 2 is third-party validated and comes in two flavors, a certification built on ISO 27001 and an attestation built on SOC 2. The STAR Level 2 Attestation is the product of a collaboration between CSA and the AICPA, in which a CPA firm conducts a SOC 2 engagement using the Trust Services Criteria together with the CCM control set. That design is the key to the whole relationship: STAR Level 2 does not discard SOC 2, it extends it with cloud-specific controls.
How STAR builds on a SOC 2 you already have
If you already hold a SOC 2 report, reaching STAR Level 2 Attestation is largely a matter of broadening scope rather than starting over. Your auditor incorporates the Cloud Controls Matrix into the engagement so the resulting report addresses both the Trust Services Criteria and the cloud-specific control domains the CCM emphasizes, such as virtualization, multi-tenancy, and supply chain. The practical effect is one combined effort that yields a SOC 2 report plus a STAR Registry entry, rather than two disconnected audits. This is far more efficient than treating them as separate programs, and it is the route most cloud providers take when a customer specifically asks for STAR. The CCM mapping also gives your security team a cloud-tailored checklist that general SOC 2 criteria leave more abstract.
When each one helps
SOC 2 is the broader, more universally recognized trust signal in North America and answers the widest range of enterprise procurement questions, so most SaaS and cloud companies start there. STAR earns its place when buyers specifically value the public registry, when you sell to organizations that use the CAIQ as their vendor questionnaire, or when cloud-specific control coverage is a differentiator in your market. Level 1 is an inexpensive way to appear in the registry and answer CAIQ-based questionnaires proactively, while Level 2 adds the weight of third-party validation. The Cloud Security Alliance has also been extending the model into AI, launching a STAR for AI track in late 2025 with an AI Controls Matrix, which signals where cloud assurance is heading.
Who should pursue STAR alongside SOC 2
Pure-play cloud infrastructure and platform providers, and vendors selling into security-conscious buyers who already consume the STAR Registry, get the most value from layering STAR onto SOC 2. A smaller SaaS company whose customers never mention CSA, CAIQ, or the CCM probably does not need it yet and is better served by a clean SOC 2. Cost for the Level 2 attestation rides largely on the incremental scope added to your SOC 2 engagement, so it is quote-based and best estimated with your audit firm rather than assumed. The decision usually comes down to a simple question: are your buyers asking for the registry entry or the CCM mapping, or just for a SOC 2 report?