Which of the following is the BEST way to assess the risk associated with using a Software as a Service (SaaS) vendor?

The BEST way to assess the risk of a SaaS vendor is to review their independent control reports, such as a Service Organization Control (SOC) 2 Type II or an ISO 27001 certification audit. These reports are prepared by qualified, independent third-party auditors and provide an objective, in-depth evaluation of the vendor's security controls over a period of time. This offers the highest level of assurance regarding the design and operational effectiveness of the vendor's security posture, which is superior to self-reported information or contractual promises.

A. Contracts establish legal obligations and security requirements but do not provide evidence that the controls are actually implemented or effective.

B. Customer references are subjective, likely biased (as vendors provide favorable ones), and do not offer a technical or objective assessment of security controls.

C. Questionnaires are a valuable due diligence tool but rely on the vendor's self-attestation, which lacks the independent verification and assurance of a third-party audit.

1. ISACA

CISM Review Manual

15th Edition. Domain 2: Information Risk Management. The manual emphasizes that for third-party risk management

obtaining and reviewing independent audit reports (e.g.

SOC reports) is a critical step. It provides a higher level of assurance than other methods like questionnaires or contract reviews because it involves an objective assessment by an external party of the controls in place and their operating effectiveness. (Specifically covered in the context of third-party service provider assessment).

2. Peltier

T. R. (2016). Information Security Risk Analysis

Third Edition. Auerbach Publications. Chapter 10

"Risk Management and the Cloud

" discusses due diligence for cloud service providers. It states

"The best way to determine whether a CSP [Cloud Service Provider] has adequate security is to ask for a copy of its third-party audit or assessment report... The SOC 2 report is the one that most organizations should request." This highlights the primacy of independent reports in vendor assessment.

3. Carnegie Mellon University

Software Engineering Institute. (2010). A Framework for Evaluating and Mitigating Software Supply Chain Security Risks (CMU/SEI-2010-TN-022). This technical note discusses methods for gaining assurance from suppliers. It differentiates between weaker forms of evidence

such as self-attestation (questionnaires)

and stronger forms

such as third-party certifications and audits

which provide more reliable and objective evidence of a supplier's security practices. (Section 3.3

"Evidence of Conformance").