The answer is that the user cannot delete the DB instance because the explicit Deny statement overrides any Allow. This is the core principle of IAM policy evaluation: an explicit Deny always takes precedence over an Allow, regardless of the order in which the policies are applied. In this scenario, even if another policy granted the DeleteDBInstance action on the prod-db resource, the explicit Deny attached to the user blocks the operation entirely. On the AWS Certified Database Specialty DBS-C01 exam, this concept tests your understanding of the "explicit Deny overrides Allow" rule, which is a frequent trap—candidates often assume that a broader Allow can bypass a specific Deny. A common memory tip is to think of Deny as a "veto power": no matter how many Allow permissions you have, a single explicit Deny kills the action. Remember the mnemonic "DENY = DO NOT EXECUTE" to reinforce that it is the final, unbreakable rule in IAM authorization.
DBS-C01 Database Security Practice Question
This DBS-C01 practice question tests your understanding of database security. 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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The user cannot delete the DB instance because the Deny statement explicitly denies it.
Option B is correct. The Deny statement explicitly denies the DeleteDBInstance action on the specific resource, and an explicit Deny overrides any Allow. Option A is wrong because the Deny overrides. Option C is wrong because the condition is not based on snapshot existence. Option D is wrong because the policy does not allow deletion.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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 can delete the DB instance only after creating a final snapshot.
Why it's wrong here
The policy does not mention snapshots; the Deny is absolute.
✗
The user can delete the DB instance because the Allow statement grants all actions.
Why it's wrong here
The explicit Deny overrides the Allow for the specific instance.
✓
The user cannot delete the DB instance because the Deny statement explicitly denies it.
Why this is correct
An explicit Deny always overrides an Allow.
Related concept
Standard ACLs match source addresses.
✗
The user can delete the DB instance because the Allow statement is broader and applies to all resources.
Why it's wrong here
The explicit Deny is more specific and overrides.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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 ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DBS-C01 ACL questions on filtering logic and placement.
Database Security — This question tests Database Security — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: The user cannot delete the DB instance because the Deny statement explicitly denies it. — Option B is correct. The Deny statement explicitly denies the DeleteDBInstance action on the specific resource, and an explicit Deny overrides any Allow. Option A is wrong because the Deny overrides. Option C is wrong because the condition is not based on snapshot existence. Option D is wrong because the policy does not allow deletion.
What should I do if I get this DBS-C01 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DBS-C01 ACL questions on filtering logic and placement.
What is the key concept behind this question?
Standard ACLs match source addresses.
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 →
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. Refer to the exhibit. An IAM policy is attached to a user. What is the effect when the user attempts to delete the RDS DB instance named 'prod-db'?
medium
A.The user can delete any other instance except 'prod-db'.
B.The user can delete the instance because the Deny statement only applies to snapshots.
✓ C.The user cannot delete the instance because of the explicit Deny statement.
D.The user can delete the instance because of the Allow on DescribeDBInstances.
Why C: The policy explicitly denies the rds:DeleteDBInstance action on the specific resource. Even though there is an Allow on other actions, an explicit Deny overrides any Allow. The user cannot delete the instance. Option A is wrong because the Deny takes precedence. Option B is wrong because the policy explicitly prevents deletion. Option D is wrong because the Deny is on the specific instance.
Variation 2. A security engineer creates the IAM policy shown in the exhibit and attaches it to an IAM user. What is the effect of this policy?
medium
A.The user can delete any database except 'prod-db'.
B.The user can describe all databases except 'prod-db'.
✓ C.The user can modify 'prod-db' but cannot delete it.
D.The user can modify any database except 'prod-db'.
Why C: Option D is correct because the policy allows DescribeDBInstances and ModifyDBInstance on all resources, but explicitly denies DeleteDBInstance on the specific database 'prod-db'. Since an explicit deny overrides any allow, the user cannot delete that database. However, the user can modify all databases including 'prod-db'. Option A is wrong because the deny is only for DeleteDBInstance. Option B is wrong because the user can modify all databases. Option C is wrong because the user can describe all databases.
Last reviewed: Jun 20, 2026
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This DBS-C01 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 DBS-C01 exam.
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