AWS KMS Key Permissions - Troubleshooting Guide

Insufficient Permissions for Customer Keys

Question

You have created a set of Customer keys using the AWS KMS service.

For the past 6 months, you have been using these customer keys.

Recently there is a new KMS feature and the default key policy is modified.

You are trying to use the new KMS feature for these customer keys but the keys seem not to have enough permissions. Which of the following options may be the reason?

Answers

Explanations

Click on the arrows to vote for the correct answer

A. B. C. D.

Answer is A.

Option A is CORRECT because to implement a new KMS feature for existing customer keys, you need to be given explicit access in the key policies.

Option B is incorrect because we do not need to give explicit access to the bucket policy.

This would not provide us the solution for the ask.

Option C is incorrect because as per the AWS documentation to reflect your new KMS features you need to work on default key policy and it is not useful to use IAM roles under this situation.

Option D is incorrect as we need to work with the default key policy associated with the KMS feature and there is no need to work on IAM users for the same.

According to the AWS documentation:

For more information on upgrading key policies please refer the following URL:

https://docs.aws.amazon.com/kms/latest/developerguide/key-policy-upgrading.html

Sure, I'd be happy to explain the possible reason why the customer keys you created using the AWS KMS service do not seem to have enough permissions to use the new KMS feature.

In AWS Key Management Service (KMS), a key policy is a JSON policy document that specifies who can use the KMS key and what actions they can perform. When a KMS key is created, a default key policy is attached to it. The default key policy allows the key creator to use the key, but it does not grant permissions to any other AWS principals. This means that unless you explicitly give access via the key policy, only the creator of the key can use it.

Based on the options provided, the most likely reason why the customer keys do not have enough permissions is that you have not explicitly given access via the key policy (Option A). This means that the new KMS feature may require additional permissions that are not included in the default key policy. To grant these permissions, you need to modify the key policy to include the required permissions.

Option B, stating that you have not explicitly given access via the bucket policy, is not relevant because bucket policies are used to control access to Amazon S3 buckets, not KMS keys.

Option C, stating that you have not given access via the IAM roles, is also not relevant because IAM roles are used to delegate access to AWS resources and services, but they do not directly grant permissions to KMS keys. However, if you are using an IAM role to access KMS keys, you may need to update the key policy to include the IAM role as an authorized principal.

Option D, stating that you have not explicitly given access via IAM users, is similar to Option A and may be a possible reason why the customer keys do not have enough permissions. However, it is less likely because IAM users are only one type of AWS principal that can be authorized to use KMS keys. Other authorized principals can include IAM roles, AWS services, and external accounts. Therefore, modifying the key policy to include the required permissions for authorized principals is a more comprehensive solution than just granting access via IAM users.

In summary, the most likely reason why the customer keys do not have enough permissions to use the new KMS feature is that you have not explicitly given access via the key policy (Option A). To fix this, you need to modify the key policy to include the required permissions for authorized principals.