What is Attestation

Attestation is a formal declaration by a third party confirming their compliance with specific security controls, regulations, or standards through documentation like SOC 2 reports, ISO certifications, or signed compliance statements. It provides verifiable evidence that vendors meet your organization's risk requirements without requiring direct audits.

Key takeaways:

• Attestations replace costly on-site audits with standardized compliance evidence
• SOC 2 Type II, ISO 27001, and PCI-DSS represent the most common attestation types
• Annual attestation collection forms the backbone of continuous vendor monitoring
• Regulatory frameworks increasingly mandate third-party attestations for critical vendors
• Attestation validity depends on scope, recency, and the credibility of the attesting party

Attestation transforms vendor risk management from trust-based relationships into evidence-based assessments. When you receive a SOC 2 Type II report from a SaaS vendor, you're holding an attestation — third-party validated proof that security controls exist and function as described.

For GRC analysts mapping controls across multiple frameworks, attestations serve as pre-validated evidence packages. A single ISO 27001 certificate can satisfy control requirements across NIST CSF, CIS Controls, and internal security policies simultaneously. This control mapping efficiency explains why 89% of enterprises now require attestations from critical vendors, according to Shared Assessments' 2023 vendor risk survey.

The regulatory push toward mandatory attestations accelerated after high-profile supply chain breaches. GDPR Article 28 requires processor attestations. New York DFS 23 NYCRR 500.11 mandates written attestations from third-party service providers. The proposed SEC cybersecurity disclosure rules explicitly reference vendor attestations as board-reportable risk indicators.

Types of Third-Party Attestations

Independent Audit Reports

SOC Reports dominate the attestation landscape. SOC 2 Type II reports examine controls over a 6-12 month period, providing point-in-time and historical evidence. The five trust service criteria — security, availability, processing integrity, confidentiality, and privacy — align with most enterprise control frameworks.

SOC 1 reports focus on financial controls, critical for vendors touching financial reporting systems. SOC 3 reports offer public-facing summaries but lack the control detail GRC teams need for proper risk scoring.

ISO Certifications provide globally recognized attestations. ISO 27001 certifies an Information Security Management System (ISMS) against 114 controls across 14 domains. ISO 27701 extends this to privacy management, creating GDPR-ready attestation packages. ISO 22301 covers business continuity — essential for critical vendor assessments.

Compliance Certifications

PCI-DSS attestations come in multiple flavors based on transaction volume. Level 1 service providers undergo annual on-site audits producing Reports on Compliance (ROCs). Smaller vendors may self-attest through SAQ forms — acceptable for low-risk relationships but insufficient for payment processors handling sensitive cardholder data.

FedRAMP provides standardized cloud security attestations for government contractors. The 325+ controls map directly to NIST 800-53, making FedRAMP packages valuable even for commercial enterprises following NIST frameworks.

Regulatory Requirements for Attestations

Financial Services

The OCC's Third-Party Risk Management Guidance expects "satisfactory evidence" of vendor controls — interpreted as independent attestations for critical vendors. FFIEC examination procedures specifically check for SOC reports and penetration testing attestations.

European Banking Authority (EBA) Guidelines on Outsourcing require "written reports" from service providers — effectively mandating attestation programs for EU financial institutions.

Healthcare

HIPAA doesn't explicitly require attestations, but Business Associate Agreements (BAAs) must include "satisfactory assurances" of safeguards. OCR audit protocols look for evidence beyond self-attestation — driving healthcare entities toward SOC 2 and HITRUST certifications.

Data Privacy

GDPR Article 28(3)(h) requires processors to "make available to the controller all information necessary to demonstrate compliance." The French DPA (CNIL) explicitly states that certifications and audit reports satisfy this requirement.

California's CPRA strengthens attestation requirements through the "reasonable security procedures" standard — undefined but interpreted through industry practice as requiring third-party validation for high-risk processors.

Implementing Attestation Programs

Collection Workflows

Successful attestation programs automate collection through vendor portals. Set annual collection windows aligned with your vendor review cycles — typically Q1 for calendar-year enterprises. Build 60-day lead times for vendors whose certifications expire mid-cycle.

Create attestation libraries mapping specific reports to control requirements:

Vendor Category	Primary Attestation	Secondary Options	Refresh Frequency
Cloud Infrastructure	SOC 2 Type II	ISO 27001, FedRAMP	Annual
SaaS Applications	SOC 2 Type II	ISO 27001, SOC 3	Annual
Payment Processors	PCI-DSS ROC	SOC 1 + SOC 2	Annual
Data Centers	SOC 2 Type II	ISO 27001, SSAE 18	Annual
Professional Services	SOC 2 Type II	ISO 27001, Self-attestation	Annual/Biennial

Validation Procedures

Raw attestation collection means nothing without validation. Check report dates — SOC 2 reports older than 12 months lose relevance. Verify certification bodies maintain accreditation (ANAB for ISO, AICPA for SOC).

Review scope statements carefully. A SOC 2 report covering only one data center helps little if your data resides elsewhere. ISO certificates scoped to "headquarters operations" miss cloud infrastructure entirely.

Risk Scoring Integration

Attestations feed directly into vendor risk scoring models. Weight attestation quality based on:

1. Independence Level: CPA-audited SOC 2 (highest) → Accredited ISO certification → Self-attestation (lowest)
2. Scope Coverage: Full environment → Partial systems → Limited sampling
3. Recency: Current period → 6-12 months old → Over 12 months
4. Historical Trending: Clean reports over multiple periods indicate control maturity

Common Attestation Pitfalls

Over-reliance on Certifications

An ISO 27001 certificate confirms an ISMS exists — not that controls effectively manage your specific risks. Match attestation scope to your risk concerns. A vendor certified for their corporate IT environment may run your data on entirely different infrastructure.

Ignoring Qualified Opinions

SOC 2 reports containing exceptions still provide value. Review management responses to exceptions. A patching delay resolved before report issuance poses less risk than unaddressed authentication weaknesses.

Attestation Shopping

Vendors may provide their "best" attestation rather than the most relevant. A SOC 3 summary report checks the attestation box but provides insufficient detail for control mapping. Specify exact report types in contracts.

Frequently Asked Questions

How do attestations differ from questionnaires in vendor assessments?

Attestations provide independent third-party validation of controls, while questionnaires rely on vendor self-reporting. Attestations carry legal liability for misrepresentation and follow standardized testing procedures, making them more reliable for high-risk vendor relationships.

What's the minimum acceptable age for a SOC 2 or ISO certification?

Reports older than 12 months generally lose acceptability. SOC 2 Type II reports should cover a period ending within the last 12 months, while ISO certifications remain valid for 3 years with required annual surveillance audits.

Can we require custom attestations from vendors?

Custom attestations increase vendor friction and costs. Instead, supplement standard attestations (SOC 2, ISO) with specific contractual warranties or targeted assessments for unique control requirements not covered in standard frameworks.

How do bridge letters work with SOC reports?

Bridge letters provide management assertions covering the gap between a SOC report's period end and present day. While not independently validated, they maintain continuity when combined with upcoming audit commitments and historical clean reports.

Should we accept SOC 2 Type I reports from new vendors?

Type I reports verify control design but not operating effectiveness. Accept them temporarily for new vendors with mandatory Type II report delivery within 12 months. Set contractual remedies if Type II reports reveal control deficiencies.

What attestation should we require from sub-processors?

Apply the same attestation standards to sub-processors handling your data. Your vendor should provide their sub-processors' attestations or demonstrate equivalent controls through their own expanded scope reports.

How do international standards like Cyber Essentials or C5 compare to SOC 2?

Regional standards often map well to established frameworks. UK's Cyber Essentials Plus provides basic assurance similar to SOC 2 Type I. Germany's C5 catalog offers cloud-specific controls comparable to SOC 2 with additional data residency focus. Evaluate based on control mapping to your requirements.