- A
Add kms:Decrypt to the developer’s IAM policy so KMS can validate the ExternalId during AssumeRole.
Why wrong: sts:ExternalId is validated by the STS AssumeRole trust policy evaluation. KMS permissions are unrelated to ExternalId condition checks and cannot fix an STS trust policy mismatch.
- B
Update the AssumeRole call in Account B to include sts:ExternalId="Fin-2026-Q2" exactly as required.
The trust policy explicitly checks the ExternalId value provided in the AssumeRole request. Supplying the exact required ExternalId satisfies the condition and allows STS to issue credentials for the role.
- C
Increase the role’s MaxSessionDuration to reduce authentication failures.
Why wrong: MaxSessionDuration impacts the lifetime of the issued session credentials, not whether the trust policy condition on sts:ExternalId is satisfied. The ExternalId mismatch would still cause AccessDenied.
- D
Remove the ExternalId condition from the trust policy to allow all AssumeRole requests.
Why wrong: Removing or weakening the ExternalId condition violates the stated security requirement and reduces protection against confused-deputy attacks.
SAA-C03 Design Secure Architectures Practice Question
This SAA-C03 practice question tests your understanding of design secure architectures. 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.
Account A has an IAM role named FinanceDataRole that is assumed by a principal in Account B. The role’s trust policy includes a condition requiring sts:ExternalId to equal "Fin-2026-Q2". A developer in Account B calls AssumeRole but receives an error: AccessDenied: ExternalId mismatch. The security team requires that you do not remove the ExternalId condition. What is the correct remediation?
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
Update the AssumeRole call in Account B to include sts:ExternalId="Fin-2026-Q2" exactly as required.
The error 'AccessDenied: ExternalId mismatch' occurs because the AssumeRole API call from Account B does not include the required sts:ExternalId parameter. The trust policy on the FinanceDataRole explicitly requires this parameter to match 'Fin-2026-Q2' as a security measure to prevent the confused deputy problem. Option B is correct because the developer must pass the exact ExternalId value in the AssumeRole request to satisfy the condition and successfully assume the role.
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.
- ✗
Add kms:Decrypt to the developer’s IAM policy so KMS can validate the ExternalId during AssumeRole.
Why it's wrong here
sts:ExternalId is validated by the STS AssumeRole trust policy evaluation. KMS permissions are unrelated to ExternalId condition checks and cannot fix an STS trust policy mismatch.
- ✓
Update the AssumeRole call in Account B to include sts:ExternalId="Fin-2026-Q2" exactly as required.
Why this is correct
The trust policy explicitly checks the ExternalId value provided in the AssumeRole request. Supplying the exact required ExternalId satisfies the condition and allows STS to issue credentials for the role.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Increase the role’s MaxSessionDuration to reduce authentication failures.
Why it's wrong here
MaxSessionDuration impacts the lifetime of the issued session credentials, not whether the trust policy condition on sts:ExternalId is satisfied. The ExternalId mismatch would still cause AccessDenied.
- ✗
Remove the ExternalId condition from the trust policy to allow all AssumeRole requests.
Why it's wrong here
Removing or weakening the ExternalId condition violates the stated security requirement and reduces protection against confused-deputy attacks.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think the ExternalId is automatically passed or that the error is due to permission issues (like KMS or session duration), when in fact the developer must explicitly include the correct ExternalId in the AssumeRole API call.
Trap categories for this question
Similar concept trap
Removing or weakening the ExternalId condition violates the stated security requirement and reduces protection against confused-deputy attacks.
Detailed technical explanation
How to think about this question
The ExternalId condition in an IAM role trust policy is a critical security mechanism to prevent the confused deputy problem, where a malicious third party tricks a service into assuming a role on its behalf. When a principal in Account B calls AssumeRole, it must include the sts:ExternalId parameter in the API request; the STS service then evaluates this against the condition in the trust policy. If the ExternalId is missing or incorrect, the request is denied with an AccessDenied error, even if the caller has valid permissions to call AssumeRole.
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 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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Design Secure Architectures — study guide chapter
Learn the concepts, then practise the questions
- →
Design Secure Architectures practice questions
Targeted practice on this topic area only
- →
All SAA-C03 questions
1,040 questions across all exam domains
- →
SAA-C03 study guide
Full concept coverage aligned to exam objectives
- →
SAA-C03 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related SAA-C03 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Design Secure Architectures practice questions
Practise SAA-C03 questions linked to Design Secure Architectures.
Design Resilient Architectures practice questions
Practise SAA-C03 questions linked to Design Resilient Architectures.
Design High-Performing Architectures practice questions
Practise SAA-C03 questions linked to Design High-Performing Architectures.
Design Cost-Optimized Architectures practice questions
Practise SAA-C03 questions linked to Design Cost-Optimized Architectures.
SAA-C03 VPC practice questions
Practise SAA-C03 questions linked to SAA-C03 VPC.
SAA-C03 S3 lifecycle policy questions
Practise SAA-C03 questions linked to SAA-C03 S3 lifecycle policy questions.
SAA-C03 RDS Multi-AZ questions
Practise SAA-C03 questions linked to SAA-C03 RDS Multi-AZ questions.
SAA-C03 IAM policy practice questions
Practise SAA-C03 questions linked to SAA-C03 IAM policy.
SAA-C03 Route 53 failover questions
Practise SAA-C03 questions linked to SAA-C03 Route 53 failover questions.
SAA-C03 CloudFront practice questions
Practise SAA-C03 questions linked to SAA-C03 CloudFront.
SAA-C03 NAT gateway questions
Practise SAA-C03 questions linked to SAA-C03 NAT gateway questions.
SAA-C03 VPC endpoint questions
Practise SAA-C03 questions linked to SAA-C03 VPC endpoint questions.
Practice this exam
Start a free SAA-C03 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this SAA-C03 question test?
Design Secure Architectures — This question tests Design Secure Architectures — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Update the AssumeRole call in Account B to include sts:ExternalId="Fin-2026-Q2" exactly as required. — The error 'AccessDenied: ExternalId mismatch' occurs because the AssumeRole API call from Account B does not include the required sts:ExternalId parameter. The trust policy on the FinanceDataRole explicitly requires this parameter to match 'Fin-2026-Q2' as a security measure to prevent the confused deputy problem. Option B is correct because the developer must pass the exact ExternalId value in the AssumeRole request to satisfy the condition and successfully assume the role.
What should I do if I get this SAA-C03 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
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 →
Keep practising
More SAA-C03 practice questions
- A content publishing system uses Lambda functions that call an unreliable third-party API. Failed events must be retaine…
- A startup runs two EC2-based workloads in the same AWS Region. Its customer-facing API is always on, and its nightly vid…
- A warehouse integration service must use shared file storage across Linux EC2 instances in multiple Availability Zones.…
- A team runs a stateless web app on Amazon EC2 behind an Application Load Balancer. During traffic spikes, new EC2 instan…
- A service in private subnets downloads product images from Amazon S3 and stores job state in DynamoDB. A NAT Gateway is…
- A static site is hosted in Amazon S3 and delivered by CloudFront. After a frontend release, the same JavaScript bundles…
Last reviewed: Jun 11, 2026
This SAA-C03 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 SAA-C03 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.