Question 747 of 1,616
SecurityhardMultiple ChoiceObjective-mapped

Quick Answer

The answer is that the IAM user in Account B must have an attached IAM policy explicitly allowing s3:GetObject on the target bucket’s ARN. This is required because cross-account S3 access is governed by a union of permissions: the resource-based bucket policy in Account A grants access to the external user, but the user’s own identity-based policy in Account B must also explicitly allow the same action. Without this, Account B’s implicit default deny blocks the request before it ever reaches Account A’s bucket policy, resulting in Access Denied. On the AWS Certified Developer Associate DVA-C02 exam, this scenario tests your understanding that cross-account access is a two-way gate—both the target account’s bucket policy and the source account’s IAM policy must permit the operation. A common trap is assuming the bucket policy alone is sufficient, so remember the “double-permission” rule: for cross-account S3, the source account must also say “yes.” Memory tip: “Both sides sign the permission slip.”

DVA-C02 Security Practice Question

This DVA-C02 practice question tests your understanding of security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A developer needs to grant a user in another AWS account (Account B) read-only access to objects in an Amazon S3 bucket owned by Account A. The developer has already added a bucket policy that grants s3:GetObject access to the IAM user in Account B. However, the user in Account B still gets Access Denied when trying to read objects. What additional configuration is required?

Question 1hardmultiple choice
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Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

The user in Account B must have an IAM policy that allows s3:GetObject on the bucket ARN

The bucket policy in Account A grants s3:GetObject access to the IAM user in Account B, but this alone is insufficient. For cross-account access, the IAM user in Account B must also have an IAM policy attached that explicitly allows s3:GetObject on the bucket ARN. Without this, the user’s own account denies the request before it reaches Account A’s bucket policy, resulting in Access Denied.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • The user in Account B must have an IAM policy that allows s3:GetObject on the bucket ARN

    Why this is correct

    Cross-account access requires both a bucket policy that grants the user permissions and an IAM policy in the user's account that allows the action. The IAM policy is necessary because the default is to deny all actions.

    Related concept

    Read the scenario before looking for a memorised answer.

  • The bucket must be made public by unchecking 'Block all public access'

    Why it's wrong here

    Making the bucket public would allow everyone access, which is too permissive and violates the principle of least privilege. The correct approach is to use a combination of bucket and IAM policies.

  • The developer must create a new IAM role in Account A and have the user in Account B assume that role

    Why it's wrong here

    While using role assumption is another valid cross-account access method, the question states the developer already used a bucket policy. The issue is likely the missing IAM user policy in Account B.

  • The user in Account B must use the S3 console instead of the AWS CLI

    Why it's wrong here

    The access denied error is a permissions issue, not a tool issue. The console and CLI both enforce IAM and bucket policies.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates assume a bucket policy alone is sufficient for cross-account access, overlooking the requirement for an explicit IAM policy in the requesting account to allow the action.

Detailed technical explanation

How to think about this question

Cross-account S3 access requires a two-step authorization: the resource-based policy (bucket policy) in the owning account must grant access to the principal, and the principal’s identity-based policy (IAM policy) in their own account must also allow the action. This is because IAM evaluates both policies, and if either denies the request, Access Denied is returned. A common real-world scenario is when a developer forgets to attach the IAM policy to the user in the consuming account, leading to a seemingly inexplicable denial despite a correct bucket policy.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.

What to study next

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FAQ

Questions learners often ask

What does this DVA-C02 question test?

Security — This question tests Security — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The user in Account B must have an IAM policy that allows s3:GetObject on the bucket ARN — The bucket policy in Account A grants s3:GetObject access to the IAM user in Account B, but this alone is insufficient. For cross-account access, the IAM user in Account B must also have an IAM policy attached that explicitly allows s3:GetObject on the bucket ARN. Without this, the user’s own account denies the request before it reaches Account A’s bucket policy, resulting in Access Denied.

What should I do if I get this DVA-C02 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Same concept, more angles

1 more ways this is tested on DVA-C02

These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.

Variation 1. A developer needs to allow users from another AWS account (account ID: 123456789012) to read objects in an S3 bucket owned by the developer's account. The developer wants to use a bucket policy and does not want to create IAM users in the other account. Which bucket policy statement achieves this securely?

medium
  • A.{"Principal": "*", "Action": "s3:GetObject", "Effect": "Allow", "Resource": "arn:aws:s3:::bucket/*", "Condition": {"StringEquals": {"aws:SourceAccount": "123456789012"}}}
  • B.{"Principal": {"AWS": "arn:aws:iam::123456789012:root"}, "Action": "s3:GetObject", "Effect": "Allow", "Resource": "arn:aws:s3:::bucket/*"}
  • C.{"Principal": {"AWS": "arn:aws:iam::123456789012:user/cross-account-user"}, "Action": "s3:GetObject", "Effect": "Allow", "Resource": "arn:aws:s3:::bucket/*"}
  • D.{"Principal": {"AWS": "arn:aws:iam::123456789012:role/cross-account-role"}, "Action": "s3:GetObject", "Effect": "Allow", "Resource": "arn:aws:s3:::bucket/*"}

Why B: Option B is correct because it uses the AWS account root principal ARN (arn:aws:iam::123456789012:root) to grant cross-account access to the S3 bucket. This allows any IAM user or role in the external account to read objects, provided the external account's administrator delegates permissions via IAM policies. The bucket policy does not require creating IAM users in the other account, aligning with the requirement.

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Last reviewed: Jun 11, 2026

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This DVA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DVA-C02 exam.