Concepts
A common strategy to enhance security is key rotation. By regularly changing encryption keys, you reduce the risk that they become compromised. In the context of preparing for the AWS Certified Developer – Associate (DVA-C02) exam, understanding how to implement and automate key rotation within AWS services is crucial.
What is Key Rotation?
Key rotation refers to the practice of regularly changing the encryption key used to secure data. The primary goal is to limit the amount of data that is encrypted with a single key, thereby reducing the impact of a potential key compromise.
Benefits of Key Rotation
- Limits Exposure: In case a key is compromised, only the data encrypted with that key is at risk.
- Meets Compliance Standards: Several industry standards and regulations mandate regular key rotation.
- Enhances Security: Regularly changing keys can make it more difficult for attackers to gain sustained access to encrypted data.
AWS Key Management Service (AWS KMS)
AWS KMS is a managed service that makes it easy to create and control the cryptographic keys used to encrypt data. AWS KMS supports both automated and manual key rotation.
Automated Key Rotation:
AWS KMS can automatically rotate the backing keys for customer master keys (CMKs) that are created in AWS KMS. The default rotation period is 365 days, but this can be changed per CMK. It’s important to note that AWS automatically rotates the backing keys, not the key material of the CMK itself. This means that the key ID and ARN remain the same, but the cryptographic material of the backing key changes.
Enabling Automated Key Rotation:
import boto3
# Create a KMS client
kms_client = boto3.client(‘kms’)
# Enable automatic key rotation for a CMK
kms_client.enable_key_rotation(KeyId=’the-cmk-id’)
Manual Key Rotation:
For manual key rotation, the developer creates a new CMK and updates all applications and resources to start using the new key. This can be a more complex process since it requires careful coordination to ensure that all data is re-encrypted with the new key, and that all applications have their references to the key updated.
Key Rotation in Other AWS Services
Some AWS services integrate with AWS KMS and they handle key rotation differently:
| AWS Service | Description of Key Rotation |
|---|---|
| Amazon S3 | Offers an option to encrypt objects using S3-managed keys or customer-managed keys through AWS KMS. S3 does not directly rotate keys but uses whatever key is specified by the user for encryption. |
| Amazon RDS | Supports the use of AWS KMS for encryption of database instances. RDS automatically rotates the keys used to encrypt the database. |
| Amazon DynamoDB | Supports automatic and manual key rotation for encryption at rest using AWS KMS. Once automatic key rotation is enabled for a DynamoDB table, you do not need to take any further action for rotation. |
| AWS Secret Manager | Helps to manage, retrieve, and rotate database credentials, API keys, and other secrets through their lifecycle. Secret Manager allows configuring rotation using a Lambda function that can periodically update the secret. |
Best Practices for Key Rotation
- Define a Rotation Policy: Establish a key rotation policy that aligns with organizational security policies and compliance requirements.
- Monitor and Audit: Regularly monitor and audit access to keys and the key rotation process.
- Automate the Process: Automating key rotation can help prevent human error and ensure keys are rotated according to schedule.
Conclusion
In preparing for the AWS Certified Developer – Associate exam, it’s essential to understand key rotation and be comfortable with implementing both automatic and manual key rotation using AWS KMS and understand how it interacts with other AWS services. Implementing key rotation might also involve updating IAM policies and applications to use the new keys seamlessly.
By understanding the mechanisms AWS provides to secure data using keys and the importance of regularly rotating these keys, candidates can better design and implement secure applications on the AWS platform.
Answer the Questions in Comment Section
True/False: In AWS, access keys consist of a secret access key and an access key ID.
- Answer: True
In AWS, access keys are used for programmatic access and they consist of two parts: an access key ID and a secret access key.
True/False: Key rotation refers to the process of regularly changing an encryption key, but it does not apply to access keys used for AWS services.
- Answer: False
Key rotation applies to all types of keys including encryption keys and access keys used for AWS services. It is a best practice to rotate these keys regularly.
Multiple select: Which of the following AWS services support automatic key rotation? (Select two)
- a) AWS KMS
- b) IAM user access keys
- c) Amazon S3
- d) AWS Secrets Manager
- Answer: a) AWS KMS, d) AWS Secrets Manager
AWS Key Management Service (KMS) supports automatic rotation for customer master keys (CMKs) and AWS Secrets Manager supports automatic rotation of secrets such as database credentials or API keys.
Single select: How often does AWS recommend that you rotate your AWS IAM access keys?
- a) Every 30 days
- b) Every 90 days
- c) At least every 180 days
- d) Once a year
- Answer: b) Every 90 days
AWS recommends that you rotate your AWS IAM access keys every 90 days or even more frequently.
True/False: Rotating the secret access key for a root account is possible directly from the AWS Management Console.
- Answer: False
Rotating keys is a recommended security measure for IAM users, not the root account. For the root account, AWS advises securing it with multi-factor authentication (MFA) and using IAM users for day-to-day tasks.
True/False: When you rotate your AWS IAM access keys, the old key is deleted immediately.
- Answer: False
When you rotate your access keys, you should first create a new key, update all applications to use the new key, and then deactivate or delete the old key to ensure no disruptions in service.
Multiple select: What steps are recommended when performing key rotation for IAM access keys? (Select two)
- a) Generate a new access key.
- b) Revoke all previous access keys immediately before creating a new one.
- c) Update all applications to use the new access key.
- d) Delete all access keys and rely on IAM roles.
- Answer: a) Generate a new access key, c) Update all applications to use the new access key
When rotating IAM access keys, it is essential to generate a new access key and update all applications with the new key before deactivating or deleting the old keys.
True/False: You can have two active access keys at the same time for an IAM user in AWS.
- Answer: True
AWS allows IAM users to have two active access keys at the same time to facilitate key rotation without interrupting service.
Single select: When automatically rotating keys in AWS Secrets Manager, which AWS service is used to invoke the rotation function?
- a) AWS Lambda
- b) Amazon EC2
- c) AWS Elastic Beanstalk
- d) Amazon RDS
- Answer: a) AWS Lambda
AWS Secrets Manager uses AWS Lambda to invoke a rotation function that defines how a secret is rotated.
True/False: When rotating keys in AWS KMS, the old CMK and the new CMK will have the same key ID.
- Answer: False
When you rotate a customer master key (CMK) in AWS KMS, a new CMK is created with a new key ID. However, the alias that points to the CMK remains the same.
Single select: Who is responsible for managing the access keys and secret keys in AWS?
- a) AWS
- b) The customer
- c) Both AWS and the customer
- d) Third-party vendors only
- Answer: b) The customer
The management of access keys and secret keys in AWS is solely the responsibility of the customer. AWS provides the tools and resources for key management but does not manage the keys for the customer.
True/False: When you enable automatic rotation for a secret in AWS Secrets Manager, the rotation period can be adjusted as needed.
- Answer: True
In AWS Secrets Manager, you can set the rotation period for a secret according to your requirements, and it can be adjusted at any time if needed.
Key rotation is essential for maintaining the security of encryption keys.
Thanks for the informative post!
Can anyone explain how AWS Key Management Service (KMS) supports key rotation?
Key rotation can be complex to implement correctly in a distributed system.
Not really a fan of AWS KMS due to its cost.
What are the benefits of automatic key rotation?
Appreciate the detailed explanation on key rotation.
Does key rotation affect the performance of the applications?