Question 1,144 of 1,748
Identity and Access ManagementmediumMultiple ChoiceObjective-mapped

Troubleshooting EC2 Start/Stop Denied: Need ec2:DescribeInstances

This SCS-C02 practice question tests your understanding of identity and access management. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: ec2:DescribeInstances. 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 security engineer is troubleshooting an IAM policy that is not working as expected. The policy allows ec2:StartInstances and ec2:StopInstances but the user gets an access denied error when trying to stop an instance. What is the most likely cause?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

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 user does not have permission to call ec2:DescribeInstances.

The correct answer is B because the AWS Management Console requires the ec2:DescribeInstances permission to list instance details. Without it, the Stop action fails even if ec2:StopInstances is allowed. Option A is incorrect because SCPs can deny actions, but the question states the policy allows the actions. Option C is incorrect because the policy does not restrict regions, and explicit deny statements are separate from allow statements, so Option D is irrelevant.

Key principle: ec2:DescribeInstances

Answer analysis

Option-by-option breakdown

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

  • A service control policy is denying the action.

    Why it's wrong here

    Incorrect. A service control policy (SCP) could deny the action, but the question indicates the IAM policy allows the action, and SCPs are applied at the OU level, not directly to the user.

  • The user does not have permission to call ec2:DescribeInstances.

    Why this is correct

    Correct. The AWS Management Console often requires ec2:DescribeInstances to display and interact with instances. Without it, the Stop action appears to fail even though the Stop permission is granted.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    ec2:DescribeInstances

  • The policy does not allow stopping instances in all regions.

    Why it's wrong here

    Incorrect. The policy does not specify region restrictions, and regions don't affect the required permissions for the Stop action.

  • There is an explicit deny statement in the policy.

    Why it's wrong here

    Incorrect. An explicit deny would override the allow, but the policy described only has allow statements. The issue is a missing dependent permission (DescribeInstances), not an explicit deny.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.

Detailed technical explanation

How to think about this question

Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.

KKey Concepts to Remember

  • ec2:DescribeInstances

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

ec2:DescribeInstances

Real-world example

How this comes up in practice

A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.

What to study next

Got this wrong? Here's your next step.

Review ec2:DescribeInstances, then practise related SCS-C02 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this SCS-C02 question test?

Identity and Access Management — This question tests Identity and Access Management — ec2:DescribeInstances.

What is the correct answer to this question?

The correct answer is: The user does not have permission to call ec2:DescribeInstances. — The correct answer is B because the AWS Management Console requires the ec2:DescribeInstances permission to list instance details. Without it, the Stop action fails even if ec2:StopInstances is allowed. Option A is incorrect because SCPs can deny actions, but the question states the policy allows the actions. Option C is incorrect because the policy does not restrict regions, and explicit deny statements are separate from allow statements, so Option D is irrelevant.

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

Review ec2:DescribeInstances, then practise related SCS-C02 questions on the same topic to reinforce the concept.

Are there clue words in this question I should notice?

Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

ec2:DescribeInstances

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Last reviewed: Jun 20, 2026

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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.