The answer is that the Glue service role lacks the required kms:Decrypt and kms:Encrypt permissions for the customer-managed KMS key. When AWS Glue ETL jobs read encrypted data from S3 or write results back, the Glue service role must have explicit KMS permissions to decrypt the source data and encrypt the output, even if the S3 bucket policy allows access. Without these actions on the key, the job fails with an 'Access Denied' error, as the encryption/decryption operation is separate from S3 data plane permissions. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of how Glue ETL KMS permission settings interact with service roles—a common trap is assuming S3 bucket policies alone control access to encrypted objects. Remember: Glue needs both kms:Decrypt and kms:Encrypt on the key, not just S3 read/write. Memory tip: "Glue must glue the key actions—Decrypt to read, Encrypt to write."
DEA-C01 Data Security and Governance Practice Question
This DEA-C01 practice question tests your understanding of data security and governance. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 company uses AWS Glue to process sensitive data stored in S3. The security team requires that all data be encrypted at rest using customer-managed KMS keys. The data engineers are encountering 'Access Denied' errors when running Glue ETL jobs. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The Glue service role does not have kms:Decrypt and kms:Encrypt permissions for the KMS key.
Option A is correct because Glue service role must have kms:Decrypt and kms:Encrypt permissions for the KMS key to read/write encrypted data from S3. Option B is incorrect because S3 bucket policies can restrict access but the error is likely due to missing KMS permissions. Option C is incorrect because KMS key policies or IAM policies can grant access to Glue role. Option D is incorrect because the issue is not about cross-account access.
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 Glue service role does not have kms:Decrypt and kms:Encrypt permissions for the KMS key.
Why this is correct
Glue needs KMS permissions to decrypt objects from S3 and encrypt output.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The KMS key policy does not allow the AWS Glue service to use the key.
Why it's wrong here
Glue uses the service role, not the Glue service principal directly.
✗
The Glue Data Catalog is encrypted with a different KMS key.
Why it's wrong here
Data Catalog encryption is separate from S3 objects.
✗
The S3 bucket policy denies access to the Glue service role.
Why it's wrong here
While possible, the error is more likely due to missing KMS permissions.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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
Got this wrong? Here's your next step.
Identify which DEA-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Data Security and Governance — This question tests Data Security and Governance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The Glue service role does not have kms:Decrypt and kms:Encrypt permissions for the KMS key. — Option A is correct because Glue service role must have kms:Decrypt and kms:Encrypt permissions for the KMS key to read/write encrypted data from S3. Option B is incorrect because S3 bucket policies can restrict access but the error is likely due to missing KMS permissions. Option C is incorrect because KMS key policies or IAM policies can grant access to Glue role. Option D is incorrect because the issue is not about cross-account access.
What should I do if I get this DEA-C01 question wrong?
Identify which DEA-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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 financial services company uses AWS Glue ETL jobs to process sensitive customer data stored in Amazon S3. The data is encrypted at rest with SSE-KMS using a customer-managed key. Recently, the security team discovered that the Glue job's IAM role has an overly permissive policy that allows the 'kms:Decrypt' action for all KMS keys in the account. The company wants to follow the principle of least privilege. The Glue job runs on a schedule and reads from a specific S3 bucket. The security team needs to update the IAM policy to restrict KMS decryption to only the specific key used for that bucket. What should they do?
medium
A.Update the policy to allow 'kms:Decrypt' with a resource of 'arn:aws:kms:us-east-1:123456789012:key/*' to cover all keys in the account.
B.Update the policy to allow 'kms:Decrypt' with a resource of '*' to ensure the job can always decrypt data.
✓ C.Update the policy to allow 'kms:Decrypt' only for the specific KMS key ARN used by the S3 bucket containing the customer data.
D.Remove the 'kms:Decrypt' action from the policy and rely on S3 bucket policies to grant decryption permissions.
Why C: Option B is correct because the IAM policy should grant 'kms:Decrypt' only for the specific KMS key ARN used by the target S3 bucket, following least privilege. Option A is wrong because using '*' for the key is overly permissive. Option C is wrong because using a wildcard in the key ARN (key/*) is not a valid ARN pattern; KMS key ARNs are specific. Option D is wrong because 'kms:Decrypt' is required for the Glue job to access encrypted data; removing it would break the job.
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This DEA-C01 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 DEA-C01 exam.
Question Discussion
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