The correct answer is unauthorized access by an external attacker. This is because an IAM role trust policy that allows any AWS account—specifically using `"Principal": {"AWS": "*"}`—means any user or service in any AWS account can call the STS `AssumeRole` API to obtain temporary credentials for that role, effectively granting all the role’s permissions to an unknown external entity. On the AWS Certified Security Specialty SCS-C02 exam, this misconfiguration tests your understanding of the principle of least privilege in trust policies and the specific risk of an overly permissive principal wildcard. A common trap is confusing this with a resource-based policy; remember that trust policies control who can assume the role, not what the role can access. For a quick memory tip, think of it as the “open-door policy” risk: if the principal is a wildcard, any account can walk right in.
SCS-C02 Identity and Access Management Practice Question
This SCS-C02 practice question tests your understanding of identity and access management. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 notices that an IAM role has a trust policy allowing any AWS account to assume it. Which attack is this misconfiguration most likely to enable?
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
✓
Unauthorized access by an external attacker
Option C is correct because an IAM role trust policy that allows any AWS account (i.e., `"Principal": {"AWS": "*"}`) to assume the role means that any user or service in any AWS account can call the STS `AssumeRole` API to obtain temporary credentials for the role. This directly enables unauthorized access by an external attacker who can discover the role ARN and assume it, gaining all permissions attached to 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.
✗
Logging bypass via CloudTrail
Why it's wrong here
Trust policy does not affect logging.
✗
Cross-service confused deputy attack
Why it's wrong here
This involves misleading a service into performing actions; not directly related to trust policy.
✓
Unauthorized access by an external attacker
Why this is correct
Any AWS account can assume the role, leading to unauthorized access.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Privilege escalation by attaching additional policies
Why it's wrong here
This would require the attacker to have existing permissions to modify policies.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse a trust policy misconfiguration with a permissions policy misconfiguration, thinking that privilege escalation (Option D) is the primary risk, when in fact the trust policy directly controls who can assume the role, making unauthorized access the immediate and most likely attack.
Detailed technical explanation
How to think about this question
Under the hood, the trust policy is evaluated by the AWS STS service when an `AssumeRole` API call is made. The `Principal` element in the trust policy defines which entities are allowed to assume the role; setting it to `"AWS": "*"` effectively grants access to every AWS account, including anonymous or external accounts. In a real-world scenario, an attacker could use tools like `aws sts assume-role` with the role ARN to obtain temporary credentials and then perform actions such as data exfiltration or resource deletion, all while the role's CloudTrail logs record the activity under the attacker's account ID.
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.
Identity and Access Management — This question tests Identity and Access Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Unauthorized access by an external attacker — Option C is correct because an IAM role trust policy that allows any AWS account (i.e., `"Principal": {"AWS": "*"}`) to assume the role means that any user or service in any AWS account can call the STS `AssumeRole` API to obtain temporary credentials for the role. This directly enables unauthorized access by an external attacker who can discover the role ARN and assume it, gaining all permissions attached to the role.
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.
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?
Read the scenario before looking for a memorised answer.
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Question Discussion
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