An IS auditor is evaluating the appropriateness of audit evidence collected during an audit of an organization's cloud security controls. The audit objective was to determine if data stored in the cloud is encrypted at rest according to policy. The auditor reviewed a screenshot of the cloud provider's console showing a checkbox for 'encryption enabled' and a signed statement from the cloud administrator confirming encryption. Which of the following statements BEST describes the sufficiency and reliability of this evidence?
- AThe evidence is reliable but insufficient, as it lacks a detailed technical specification of the encryption algorithm used.
- BThe evidence is insufficient because a single screenshot and attestation are never enough for cloud security controls.
- CThe evidence may be sufficient, but its reliability is questionable without independent verification of the encryption's implementation.
- DThe evidence is sufficient and highly reliable, as it combines visual confirmation and administrative attestation.
Show answer & explanationAnswer & explanation
Correct answer: C. The evidence may be sufficient, but its reliability is questionable without independent verification of the encryption's implementation.
While a screenshot provides some visual confirmation and an administrator's statement offers attestation, both can be manipulated or reflect incorrect understanding. For critical controls like encryption at rest, independent verification (e.g., attempting to access data without keys, reviewing configuration files, or using third-party tools) is necessary to ensure the control is *actually* implemented and effective, not just reported as such. Thus, sufficiency might be there in quantity, but reliability is weak without deeper verification.
Why the other options are wrong
- A. While the algorithm specification is good to know, the primary concern for reliability is *whether encryption is actually active and effective*, which isn't confirmed by just a screenshot and attestation.
- B. The claim 'never enough' is an overstatement; the issue is more about reliability than sheer quantity for this type of evidence.
- D. Reliability is not 'highly reliable' without independent verification, as both pieces of evidence could be misleading.
Sufficiency and Reliability of Audit Evidence
Sufficiency refers to the quantity of audit evidence, while reliability refers to its quality, trustworthiness, and ability to support audit conclusions.
- Sufficiency is judged by the amount of evidence.
- Reliability is influenced by source (independent vs. internal), nature (original vs. copy), and method of collection.
- Evidence from independent sources is generally more reliable.
- Direct evidence is more reliable than indirect evidence.
Memory trick: Enough evidence, but is it true?