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Question 39 of 1,616

Security →mediumMultiple ChoiceObjective-mapped

Quick Answer

The correct approach is to create an IAM role with permissions to the S3 bucket and attach it to the EC2 instance profile. This works because the instance profile allows the EC2 instance to assume the IAM role and retrieve temporary security credentials from AWS Security Token Service (STS) via the instance metadata service, eliminating the need to store any long-term credentials on the instance. On the AWS Certified Developer Associate DVA-C02 exam, this scenario tests your understanding of least privilege and secure credential management—a common trap is choosing access keys stored on the instance or hardcoded in the application, which violates security best practices. Remember that instance profiles are the only way to grant EC2 access to S3 without embedding credentials. A helpful memory tip: “Profile the role, not the key” — always attach an IAM role to the instance profile for temporary, automatic credentials.

DVA-C02 Security Practice Question

This DVA-C02 practice question tests your understanding of 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. A key principle to apply: iAM roles provide temporary, auto-rotating credentials for EC2 instances.. 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 runs an application on Amazon EC2 instances that need to read files from an Amazon S3 bucket. The developer must grant access to the S3 bucket without storing long-term credentials on the instances. Which approach should the developer use?

Question 1mediummultiple choice

Full question →

A
Store the access key ID and secret access key in environment variables on the EC2 instance.
Why wrong: Storing long-term credentials in environment variables is insecure and violates best practices for credential management.
B
Create an IAM role with permissions to the S3 bucket and attach it to the EC2 instance profile.
An IAM role provides temporary credentials automatically rotated by AWS, which is the secure and recommended approach.
C
Use an S3 bucket policy that grants access to the EC2 instance's public IP address.
Why wrong: Bucket policies can grant access based on IP addresses, but this is not secure as IPs can change and it does not use temporary credentials. Additionally, the instance's role is still needed.
D
Store the credentials in AWS Secrets Manager and have the application retrieve them at startup.
Why wrong: While Secrets Manager improves security over plaintext storage, it still involves long-term credentials that could be rotated, but the application would need to handle rotation. The IAM role approach is simpler and more secure for EC2 access.

Full breakdown with real-world context →

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

✓

Create an IAM role with permissions to the S3 bucket and attach it to the EC2 instance profile.

Option B is correct because using an IAM role attached to an EC2 instance profile allows the application to obtain temporary security credentials from the AWS Security Token Service (STS) via the instance metadata service. This eliminates the need to store long-term credentials on the instance, adhering to the principle of least privilege and improving security posture.

Key principle: IAM roles provide temporary, auto-rotating credentials for EC2 instances.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Store the access key ID and secret access key in environment variables on the EC2 instance.
Why it's wrong here
Storing long-term credentials in environment variables is insecure and violates best practices for credential management.
✓
Create an IAM role with permissions to the S3 bucket and attach it to the EC2 instance profile.
Why this is correct
An IAM role provides temporary credentials automatically rotated by AWS, which is the secure and recommended approach.
Related concept
IAM roles provide temporary, auto-rotating credentials for EC2 instances.
✗
Use an S3 bucket policy that grants access to the EC2 instance's public IP address.
Why it's wrong here
Bucket policies can grant access based on IP addresses, but this is not secure as IPs can change and it does not use temporary credentials. Additionally, the instance's role is still needed.
✗
Store the credentials in AWS Secrets Manager and have the application retrieve them at startup.
Why it's wrong here
While Secrets Manager improves security over plaintext storage, it still involves long-term credentials that could be rotated, but the application would need to handle rotation. The IAM role approach is simpler and more secure for EC2 access.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may think storing credentials in environment variables or Secrets Manager is acceptable, but the question explicitly requires no long-term credentials on the instance, making the IAM role the only correct answer that leverages temporary credentials via the instance metadata service.

Detailed technical explanation

How to think about this question

When an IAM role is attached to an EC2 instance profile, the instance automatically retrieves temporary credentials from the instance metadata service (IMDS) at http://169.254.169.254/latest/meta-data/iam/security-credentials/. These credentials are rotated automatically by AWS STS, typically with a default expiration of 6 hours, and the AWS SDKs handle refreshing them transparently. This mechanism is fundamental to secure credential management in AWS and is a core concept tested in the DVA-C02 exam.

KKey Concepts to Remember

IAM roles provide temporary, auto-rotating credentials for EC2 instances.
EC2 instances assume roles via an instance profile.
Applications use AWS SDKs to automatically leverage instance role credentials.
IAM roles eliminate the need to store long-term credentials on instances.

TExam Day Tips

Watch for words such as best, first, most likely and least administrative effort.
Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

IAM roles provide temporary, auto-rotating credentials for EC2 instances.

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 iAM roles provide temporary, auto-rotating credentials for EC2 instances., then practise related DVA-C02 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this DVA-C02 question test?

Security — This question tests Security — IAM roles provide temporary, auto-rotating credentials for EC2 instances..

What is the correct answer to this question?

The correct answer is: Create an IAM role with permissions to the S3 bucket and attach it to the EC2 instance profile. — Option B is correct because using an IAM role attached to an EC2 instance profile allows the application to obtain temporary security credentials from the AWS Security Token Service (STS) via the instance metadata service. This eliminates the need to store long-term credentials on the instance, adhering to the principle of least privilege and improving security posture.

What should I do if I get this DVA-C02 question wrong?

Review iAM roles provide temporary, auto-rotating credentials for EC2 instances., then practise related DVA-C02 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

IAM roles provide temporary, auto-rotating credentials for EC2 instances.

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Same concept, more angles

1 more ways this is tested on DVA-C02

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 company runs an application on Amazon EC2 instances that need to read data from an Amazon DynamoDB table. The developer must grant access to DynamoDB without storing any long-term credentials on the instance. Which approach should the developer use?

easy

A.Store the AWS access key and secret key in a configuration file.
✓ B.Use an IAM role and attach it to the EC2 instance profile.
C.Use an IAM user and store credentials in AWS Secrets Manager.
D.Use the DynamoDB table's resource-based policy to allow the EC2 instance.

Why B: Option B is correct because attaching an IAM role to an EC2 instance profile allows the instance to obtain temporary security credentials from the AWS Security Token Service (STS) via the instance metadata service. This eliminates the need to store long-term credentials on the instance, adhering to the principle of least privilege and improving security posture.

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This DVA-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 DVA-C02 exam.