The answer is that the VPC has an IAM policy attached that denies the ec2:RunInstances action. This is correct because even when a user holds a broad managed policy like AmazonEC2FullAccess, a resource-based policy attached directly to the VPC can explicitly deny the launch action, overriding the user-level allow. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of IAM policy evaluation logic, specifically that explicit denies at the resource level take precedence over allows at the user level. A common trap is assuming full access policies guarantee success, but they do not account for VPC-level restrictions or subnet-level IAM policies. Remember the memory tip: “Full access does not mean full power—check the resource policy for the deny tower.”
SCS-C02 Identity and Access Management Practice Question
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. 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.
An administrator is troubleshooting an issue where an IAM user cannot launch an EC2 instance in a specific VPC. The user has the AmazonEC2FullAccess policy attached. 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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The VPC has an IAM policy attached that denies the ec2:RunInstances action.
Option A is correct because the VPC might have a resource-based policy or a network ACL (though IAM is more common) that restricts actions. However, a more precise answer is that the user may not have permissions to use the subnet or security group. Option B is wrong because the user has full access. Option C is wrong because the user has full access. Option D is wrong because the key pair is not an IAM resource.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The user's permissions boundary blocks EC2 actions.
Why it's wrong here
A permissions boundary would override the full access policy, but the boundary would need to explicitly deny EC2.
✗
The user has exceeded the maximum number of EC2 instances allowed.
Why it's wrong here
Service limits would cause an error, but the user has full access.
✓
The VPC has an IAM policy attached that denies the ec2:RunInstances action.
Why this is correct
VPCs can have resource-based policies (e.g., VPC endpoint policies) that restrict actions.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Key pairs are not IAM resources; they can be used by any user with launch permissions.
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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 block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related SCS-C02 subnetting questions on CIDR, address ranges, and subnet selection.
Identity and Access Management — This question tests Identity and Access Management — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: The VPC has an IAM policy attached that denies the ec2:RunInstances action. — Option A is correct because the VPC might have a resource-based policy or a network ACL (though IAM is more common) that restricts actions. However, a more precise answer is that the user may not have permissions to use the subnet or security group. Option B is wrong because the user has full access. Option C is wrong because the user has full access. Option D is wrong because the key pair is not an IAM resource.
What should I do if I get this SCS-C02 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related SCS-C02 subnetting questions on CIDR, address ranges, and subnet selection.
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?
CIDR notation defines the prefix length.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.