Cis AWS Foundations 6.1.1

Ensure EBS volume encryption is enabled in all regions

Description

Elastic Compute Cloud (EC2) supports encryption at rest when using the Elastic Block Store (EBS) service. While disabled by default, forcing encryption at EBS volume creation is supported.

Rationale

Encrypting data at rest reduces the likelihood of unintentional exposure and can nullify the impact of disclosure if the encryption remains unbroken.

Impact

Losing access to or removing the KMS key used by the EBS volumes will result in the inability to access the volumes.

Audit Procedure

Using AWS Console

1. Login to the AWS Management Console and open the Amazon EC2 console using https://console.aws.amazon.com/ec2/.
2. Under Account attributes, click Data Protection and Security.
3. Under EBS encryption, verify that Always encrypt new EBS volumes displays Enabled.
4. Repeat for each region in use.

Note: EBS volume encryption is configured per region.

Using AWS CLI

1. Run the following command:

aws --region <region> ec2 get-ebs-encryption-by-default

2. Verify that "EbsEncryptionByDefault": true is displayed.
3. Repeat for each region in use.

Expected Result

"EbsEncryptionByDefault": true should be displayed for every region in use.

Remediation

Using AWS Console

1. Login to the AWS Management Console and open the Amazon EC2 console using https://console.aws.amazon.com/ec2/.
2. Under Account attributes, click Data protection and security.
3. Under EBS encryption, Click Manage.
4. Check the Enable box to default encryption.
5. Click Update EBS encryption.
6. Repeat for each region in which EBS volume encryption is not enabled by default.

Using AWS CLI

1. Run the following command:

aws --region <region> ec2 enable-ebs-encryption-by-default

2. Verify that "EbsEncryptionByDefault": true is displayed.
3. Repeat for each region in which EBS volume encryption is not enabled by default.

Note: EBS volume encryption is configured per region.

Default Value

By default, EBS volume encryption is disabled. It must be manually enabled per region; otherwise, new EBS volumes are created unencrypted.

References

1. https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSEncryption.html
2. https://aws.amazon.com/blogs/aws/new-opt-in-to-default-encryption-for-new-ebs-volumes/

Additional Information

Default EBS volume encryption only applies to newly created EBS volumes; existing EBS volumes are not converted automatically.

CIS Controls

MITRE ATT&CK Mappings

Profile

Level 1 | Automated