SCS-C02 Infrastructure Security Practice Question
Exhibit
Refer to the exhibit.
Resources:
MyBucket:
Type: AWS::S3::Bucket
Properties:
BucketName: my-secure-bucket
PublicAccessBlockConfiguration:
BlockPublicAcls: true
BlockPublicPolicy: true
IgnorePublicAcls: true
RestrictPublicBuckets: true
BucketPolicy:
Statement:
- Effect: Allow
Principal:
AWS: arn:aws:iam::123456789012:role/DataAccessRole
Action: s3:GetObject
Resource: !Sub arn:aws:s3:::${MyBucket}/*Refer to the exhibit. A security engineer deploys this CloudFormation template. An IAM role 'DataAccessRole' in the same account needs to read objects from the bucket. After deployment, users assume the role but get AccessDenied errors when trying to read objects. What is the MOST likely cause?
⚠ Common exam trap
The SCS-C02 exam often tests the misconception that a bucket policy alone is sufficient to grant cross-account access, without considering that PublicAccessBlockConfiguration can silently override it, leading candidates to overlook this setting.
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 PublicAccessBlockConfiguration is blocking the bucket policy.
The PublicAccessBlockConfiguration at the account or bucket level overrides any bucket policy that grants public or cross-account access. Even though the bucket policy may allow the DataAccessRole to read objects, the PublicAccessBlockConfiguration blocks all public or cross-account access, causing AccessDenied errors. This is the most likely cause because the bucket policy is effectively ignored when public access blocks are enabled.
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 IAM role is not attached to the EC2 instance profile.
Why it's wrong here
The role is assumed directly, not via instance profile.
- ✗
The bucket is encrypted with SSE-KMS and the role lacks KMS permissions.
Why it's wrong here
No encryption is specified in the template.
- ✓
The PublicAccessBlockConfiguration is blocking the bucket policy.
Why this is correct
The settings BlockPublicPolicy and RestrictPublicBuckets can prevent the policy from granting access even to specific roles.
- ✗
The role does not have s3:ListBucket permission.
Why it's wrong here
GetObject does not require ListBucket.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SCS-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 SCS-C02 exam.