mediumMultiple ChoiceObjective-mapped
CAS-004 Practice Question: Refer to the exhibit
Network Topology
Refer to the exhibit. A security engineer reviews the S3 bucket policy. Which of the following is the most concerning security issue?
⚠ Common exam trap
CompTIA CASP+ often tests the distinction between `s3:ListBucket` (listing object names) and `s3:GetObject` (reading object contents), tricking candidates into thinking listing is the most severe when actually public read access to object data is the critical risk.
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 policy allows public read access to all objects in the bucket
The S3 bucket policy explicitly grants the `s3:GetObject` action to `"Principal": "*"`, which allows any unauthenticated user (public) to read all objects in the bucket. This is a critical misconfiguration that exposes sensitive data to the internet, often leading to data breaches. The policy does not restrict access by IP, referer, or any condition, making it a direct violation of the principle of least privilege.
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 policy does not require encryption in transit
Why it's wrong here
Encryption in transit is not controlled by bucket policies; it is configured separately via endpoints or bucket policies that deny HTTP requests.
- ✗
The policy uses the incorrect version of the policy language
Why it's wrong here
The version 2012-10-17 is the current and correct version for IAM policies.
- ✗
The policy allows any user to list the objects in the bucket
Why it's wrong here
The action is s3:GetObject, not s3:ListBucket, so listing is not allowed.
- ✓
The policy allows public read access to all objects in the bucket
Why this is correct
Principal: * with s3:GetObject allows anonymous read access to all objects.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
Related to this question
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.