Data protection in AWS Certificate Manager - AWS Certificate Manager
Security for certificate private keys

Data protection in AWS Certificate Manager

The AWS shared responsibility model applies to data protection in AWS Certificate Manager. As described in this model, AWS is responsible for protecting the global infrastructure that runs all of the AWS Cloud. You are responsible for maintaining control over your content that is hosted on this infrastructure. You are also responsible for the security configuration and management tasks for the AWS services that you use. For more information about data privacy, see the Data Privacy FAQ. For information about data protection in Europe, see the AWS Shared Responsibility Model and GDPR blog post on the AWS Security Blog.

For data protection purposes, we recommend that you protect AWS account credentials and set up individual users with AWS IAM Identity Center or AWS Identity and Access Management (IAM). That way, each user is given only the permissions necessary to fulfill their job duties. We also recommend that you secure your data in the following ways:

  • Use multi-factor authentication (MFA) with each account.

  • Use SSL/TLS to communicate with AWS resources. We require TLS 1.2 and recommend TLS 1.3.

  • Set up API and user activity logging with AWS CloudTrail.

  • Use AWS encryption solutions, along with all default security controls within AWS services.

  • Use advanced managed security services such as Amazon Macie, which assists in discovering and securing sensitive data that is stored in Amazon S3.

  • If you require FIPS 140-2 validated cryptographic modules when accessing AWS through a command line interface or an API, use a FIPS endpoint. For more information about the available FIPS endpoints, see Federal Information Processing Standard (FIPS) 140-2.

We strongly recommend that you never put confidential or sensitive information, such as your customers' email addresses, into tags or free-form text fields such as a Name field. This includes when you work with ACM or other AWS services using the console, API, AWS CLI, or AWS SDKs. Any data that you enter into tags or free-form text fields used for names may be used for billing or diagnostic logs. If you provide a URL to an external server, we strongly recommend that you do not include credentials information in the URL to validate your request to that server.

Security for certificate private keys

When you request a public certificate, AWS Certificate Manager (ACM) generates a public/private key pair. For imported certificates, you generate the key pair. The public key becomes part of the certificate. ACM stores the certificate and its corresponding private key, and uses AWS Key Management Service (AWS KMS) to help protect the private key. The process works like this:

  1. The first time you request or import a certificate in an AWS Region, ACM creates a managed AWS KMS key with the alias aws/acm. This KMS key is unique in each AWS account and each AWS Region.

  2. ACM uses this KMS key to encrypt the certificate's private key. ACM stores only an encrypted version of the private key; ACM does not store the private key in plaintext form. ACM uses the same KMS key to encrypt the private keys for all certificates in a specific AWS account and a specific AWS Region.

  3. When you associate the certificate with a service that is integrated with AWS Certificate Manager, ACM sends the certificate and the encrypted private key to the service. A grant is also created in AWS KMS that allows the service to use the KMS key to decrypt the certificate's private key. For more information about grants, see Using Grants in the AWS Key Management Service Developer Guide. For more information about services supported by ACM, see Services integrated with AWS Certificate Manager.

    Note

    You have control over the automatically created AWS KMS grant. If you delete this grant for any reason, you lose ACM functionality for the integrated service.

  4. Integrated services use the KMS key to decrypt the private key. Then the service uses the certificate and the decrypted (plaintext) private key to establish secure communication channels (SSL/TLS sessions) with its clients.

  5. When the certificate is disassociated from an integrated service, the grant created in step 3 is retired. This means the service can no longer use the KMS key to decrypt the certificate's private key.