This SCS-C02 practice question tests your understanding of infrastructure security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 has an EC2 instance that needs to access an S3 bucket. The security team wants to use the principle of least privilege. Which method should be used to grant access?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "least"
Why it matters: You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create an IAM role with an S3 access policy and attach it to the EC2 instance profile.
Option D is correct because an IAM role assigned to the EC2 instance is the best practice. Option A is wrong because access keys stored on the instance are less secure. Option B is wrong because a bucket policy with a principal of the instance ID is not possible; bucket policies use IAM principals. Option C is wrong because security groups do not grant access to S3.
Key principle: Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged 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.
✗
Use a security group to allow outbound traffic to S3.
Why it's wrong here
Security groups control network traffic, not API access.
✗
Store AWS access keys on the instance and use them in the application.
Why it's wrong here
Access keys can be compromised; best practice is to use roles.
✓
Create an IAM role with an S3 access policy and attach it to the EC2 instance profile.
Why this is correct
This is the secure and recommended method.
Clue confirmation
The clue word "least" in the question point toward this answer.
Related concept
Authentication checks who the user is.
✗
Create a bucket policy that grants access to the EC2 instance ID.
Why it's wrong here
Bucket policies cannot reference EC2 instance IDs; they reference IAM principals.
Common exam traps
Common exam trap: authentication is not authorization
Logging in proves the user can authenticate. It does not automatically mean the user is allowed to enter privileged or configuration mode. Watch for AAA authorization, privilege level and command authorization details.
Detailed technical explanation
How to think about this question
This kind of question is testing the difference between identity and permission. A user may successfully log in to a router because authentication is working, but still fail to enter configuration mode because authorization is missing, misconfigured or mapped to a lower privilege level.
KKey Concepts to Remember
Authentication checks who the user is.
Authorization controls what the user is allowed to do after login.
Privilege levels affect access to EXEC and configuration commands.
AAA, TACACS+ and RADIUS can separate login success from command access.
TExam Day Tips
→Do not assume successful login means full administrative access.
→Look for words such as cannot enter configuration mode, privilege level, authorization or command access.
→Separate login problems from permission problems before choosing the answer.
Key takeaway
Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
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 Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related SCS-C02 questions on access control and AAA configuration.
Infrastructure Security — This question tests Infrastructure Security — Authentication checks who the user is..
What is the correct answer to this question?
The correct answer is: Create an IAM role with an S3 access policy and attach it to the EC2 instance profile. — Option D is correct because an IAM role assigned to the EC2 instance is the best practice. Option A is wrong because access keys stored on the instance are less secure. Option B is wrong because a bucket policy with a principal of the instance ID is not possible; bucket policies use IAM principals. Option C is wrong because security groups do not grant access to S3.
What should I do if I get this SCS-C02 question wrong?
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related SCS-C02 questions on access control and AAA configuration.
Are there clue words in this question I should notice?
Yes — watch for: "least". You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
What is the key concept behind this question?
Authentication checks who the user is.
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Question Discussion
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