The answer is that the IAM policy condition requires encryption to be AES256, which corresponds to SSE-S3, but the bucket uses SSE-KMS, causing the read to fail. This happens because the condition in the policy explicitly checks the `s3:x-amz-server-side-encryption` header, and when SageMaker sends the request to read the model file, it does not match the required `AES256` value—the bucket’s KMS encryption uses `aws:kms` instead. On the AWS Certified Machine Learning Engineer Associate MLA-C01 exam, this tests your understanding of how IAM policy conditions interact with S3 encryption types, a common trap where candidates overlook that SSE-KMS and SSE-S3 are mutually exclusive in condition keys. To avoid this, remember the memory tip: “AES256 is SSE-S3, aws:kms is KMS—match the condition to the bucket’s key.”
MLA-C01 Practice Question: ML Solution Monitoring, Maintenance and Security
This MLA-C01 practice question tests your understanding of ml solution monitoring, maintenance and security. 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.
Refer to the exhibit. A data scientist uses a SageMaker notebook instance to read a model file from S3 bucket 'my-bucket'. The bucket uses SSE-KMS encryption with a KMS key. The IAM role attached to the notebook has the above policy. However, reading the file fails. What is the MOST likely reason?
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 condition requires encryption to be AES256, which is SSE-S3, but the bucket uses KMS.
The S3 condition requires server-side encryption to be AES256 (SSE-S3), but the bucket uses SSE-KMS, so the S3 request does not satisfy the condition, denying access.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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 resource ARN for S3 does not include the bucket itself (only objects inside).
Why it's wrong here
For GetObject, the object ARN is sufficient; the bucket ARN is not required.
✗
The policy allows s3:GetObject only if server-side encryption is AES256, but the bucket uses KMS.
Why it's wrong here
This is partially correct but less precise; the condition demands AES256 header, not the actual encryption type.
✓
The condition requires encryption to be AES256, which is SSE-S3, but the bucket uses KMS.
Why this is correct
Correct. The condition checks for 'AES256' header, but SSE-KMS uses 'aws:kms', so the condition fails and access is denied.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Standard ACLs match source addresses.
✗
The kms key ARN is incorrect.
Why it's wrong here
The key ARN appears valid, and KMS permission is given, but the S3 condition is the blocking issue.
✗
The policy allows kms:Decrypt but does not allow kms:GenerateDataKey.
Why it's wrong here
GenerateDataKey is not needed for reading an existing object; Decrypt is sufficient.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related MLA-C01 ACL questions on filtering logic and placement.
ML Solution Monitoring, Maintenance and Security — This question tests ML Solution Monitoring, Maintenance and Security — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: The condition requires encryption to be AES256, which is SSE-S3, but the bucket uses KMS. — The S3 condition requires server-side encryption to be AES256 (SSE-S3), but the bucket uses SSE-KMS, so the S3 request does not satisfy the condition, denying access.
What should I do if I get this MLA-C01 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related MLA-C01 ACL questions on filtering logic and placement.
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?
Standard ACLs match source addresses.
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 team is deploying a real-time inference endpoint in SageMaker. The model requires access to an S3 bucket containing customer data, which is encrypted with SSE-KMS. The team needs to ensure that the endpoint can decrypt the data. Which IAM role configuration is necessary?
hard
A.Add kms:GenerateDataKey permission to the SageMaker execution role.
B.Attach a policy to the S3 bucket granting s3:GetObject to the KMS key.
✓ C.Add kms:Decrypt permission to the SageMaker execution role for the specific KMS key.
D.Configure the endpoint to assume the S3 bucket's IAM role.
Why C: Option A is correct because the SageMaker execution role must have permission to use the KMS key to decrypt the S3 objects. Option B is wrong because the endpoint role needs the decrypt permission, not grant to S3. Option C is insufficient because the role must have kms:Decrypt. Option D is incorrect because SageMaker does not assume a role from S3.
Last reviewed: Jun 23, 2026
Question Discussion
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This MLA-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 MLA-C01 exam.
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