The answer is to use an IAM policy that denies ec2:RunInstances unless the request includes the cost center tag. This is correct because the policy leverages the `aws:RequestTag` condition key to enforce the tag at launch time, proactively blocking any API call that omits the required tag rather than relying on post-launch audits or remediation scripts. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of IAM policy conditions for preventive controls versus detective controls like AWS Config rules; a common trap is choosing a reactive solution such as a Lambda function that terminates untagged instances, which still allows a window of non-compliance. Remember the key distinction: deny-based policies using `aws:RequestTag` enforce compliance at the moment of the API call, while allow-based policies or resource-based tags only guide behavior. Memory tip: “Deny at the door, don’t clean the floor”—if you deny the launch without the tag, you never have to clean up untagged instances.
SCS-C02 Management and Security Governance Practice Question
This SCS-C02 practice question tests your understanding of management and security governance. 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 security engineer needs to ensure that all EC2 instances launched in a development account are tagged with a cost center. What is the most effective way to enforce this?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use an IAM policy that denies ec2:RunInstances unless the request includes the cost center tag
Option D is correct because using an IAM policy with a condition key (e.g., `aws:RequestTag`) that denies `ec2:RunInstances` unless the `cost center` tag is specified in the API call enforces tagging at launch time. This prevents any untagged instance from being created, providing proactive enforcement rather than reactive detection or remediation.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 AWS Config to detect untagged instances and send alerts
Why it's wrong here
Detective, not preventive.
✗
Use AWS Systems Manager to tag instances after launch
Why it's wrong here
Reactive, not preventive.
✗
Create a tag policy in AWS Organizations requiring the cost center tag
Why it's wrong here
Tag policies only enforce on existing resources, not on launch.
✓
Use an IAM policy that denies ec2:RunInstances unless the request includes the cost center tag
Why this is correct
This prevents launching instances without the required tag.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose AWS Config (Option A) because it is a common governance tool, but they miss that Config only detects non-compliance after the fact, whereas IAM policies provide preventive enforcement at the API level.
Detailed technical explanation
How to think about this question
The IAM policy uses the `aws:RequestTag` condition key to require the `cost center` tag in the `ec2:RunInstances` request. If the tag is missing, the API call is denied with an `AccessDenied` error. This approach leverages AWS's attribute-based access control (ABAC) and is evaluated before the instance is created, ensuring zero untagged instances. Note that this policy must be combined with a `ForAnyValue:StringEquals` condition to allow multiple tag values, and it does not prevent users from adding the tag with an incorrect value unless further conditions are applied.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Management and Security Governance — This question tests Management and Security Governance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use an IAM policy that denies ec2:RunInstances unless the request includes the cost center tag — Option D is correct because using an IAM policy with a condition key (e.g., `aws:RequestTag`) that denies `ec2:RunInstances` unless the `cost center` tag is specified in the API call enforces tagging at launch time. This prevents any untagged instance from being created, providing proactive enforcement rather than reactive detection or remediation.
What should I do if I get this SCS-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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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 security engineer notices that an IAM user has permissions to launch EC2 instances but the engineer wants to ensure that all new instances are automatically tagged with the creator's user name. What is the most efficient way to enforce this?
medium
A.Use AWS CloudTrail to monitor and alert on untagged instances.
✓ B.Add an IAM policy to the user that uses a condition key 'aws:RequestTag/Creator' with a value '${aws:username}'.
C.Use AWS Config rules to automatically tag resources after creation.
D.Create an SCP that denies EC2:RunInstances unless the request includes a 'Creator' tag with the user name.
Why B: Using a service control policy (SCP) with a condition that requires tagging on EC2 RunInstances is not possible because SCPs cannot enforce tagging; they can only deny if tags are missing. Option B is the most efficient: using IAM policy with a condition that requires the tag 'Creator' to equal the IAM user name. Option A is incorrect because SCPs cannot enforce tagging. Option C is overly complex. Option D is incorrect because CloudTrail does not enforce tagging.
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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.
Question Discussion
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