Question 40
An architect is validating an enterprise AWS migration plan, the decisive constraint is: An external vendor must assume a role without allowing confused-deputy access. Which technical choice resolves the stated issue?
Explanation
Correct Answer
Require a vendor-specific external ID in the role trust-policy condition. The external ID binds role assumption to the intended customer relationship.
Incorrect Answers
Grant the instance role permissions and configure the destination bucket resource policy as required solves the related scenario A service running on EC2 needs to access an S3 bucket in another account; cross-account access must satisfy both principal authorization and resource-side trust or policy.
Although Configure a narrowly scoped cross-account IAM role trusted by the security account and use STS AssumeRole can be valid when An auditing application in a security account must list resources in member accounts without long-lived keys, it targets a different technical condition. Temporary role sessions avoid distributing persistent credentials across accounts.
Remove the organizational SCP deny if authorized while preserving least-privilege IAM controls would address a different requirement: An assumed role's policy allows an action but the member account SCP explicitly denies it. SCP denies form a permissions ceiling that IAM allows cannot override.