hardMultiple Choice
Why Relying on Private IP Ranges in S3 Bucket Policies Creates a Vulnerability
Exhibit
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::example-bucket/*"
}
]
}Refer to the exhibit. A cloud security engineer is reviewing an AWS S3 bucket policy. What security issue does the policy contain?
⚠ Common exam trap
CAS-005 often tests whether candidates can distinguish security issues that belong in a bucket policy (public access, overly broad principals) from those configured elsewhere (encryption, logging, versioning), tricking them into selecting non-policy settings.
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
✓
Public read access is allowed
The S3 bucket policy grants read access to all principals, typically via a Principal of "*" combined with an s3:GetObject action, which exposes every object in the bucket to anonymous or any AWS account. This is the classic public-read misconfiguration that has caused numerous high-profile data breaches, so the identified security issue is public read access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
No server-side encryption is specified
Why it's wrong here
The question asks what is wrong with the policy's access logic; encryption is configured on the bucket or object, not in a bucket policy, so its absence is not a policy flaw. Encryption settings belong in a separate review of default bucket encryption configuration.
- ✓
Public read access is allowed
Why this is correct
The bucket policy grants read permission to the Everyone or AllUsers principal, meaning any unauthenticated internet user can list and download objects. That wildcard principal is the specific flaw, exposing stored data publicly regardless of other conditions.
- ✗
No version ID is specified in the resource
Why it's wrong here
Omitting a version ID in the resource targets all object versions, which is normal for policy statements and not itself a security issue. Specifying version IDs matters when granting access to one immutable object version, such as in legal-hold scenarios.
- ✗
No logging is enabled for the bucket
Why it's wrong here
Bucket policy documents grant or deny principals access; logging is configured separately via S3 server access logging or CloudTrail data events, so its absence is not a policy defect. Reviewers often conflate policy content with bucket configuration, but logging would be the answer only if the stem asked about auditability rather than the policy itself.
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
About these practice questions
This CAS-005 question is part of Courseiva's 973-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
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.