Cis AWS Compute 2.2.1

Ensure EBS volume encryption is enabled

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 that it is unintentionally exposed and can nullify the impact of disclosure if the encryption remains unbroken.

Impact

Enabling EBS encryption by default applies to all new volumes. Existing unencrypted volumes are not affected. This is configured per region.

Audit Procedure

Using AWS CLI

1. Run:

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

2. Verify that "EbsEncryptionByDefault": true is displayed.
3. Review every region in-use.

Note: EBS volume encryption is configured per region.

Using AWS Console

1. Login to the EC2 console using https://console.aws.amazon.com/ec2/
2. Under Account attributes, click EBS encryption.
3. Verify Always encrypt new EBS volumes displays Enabled.
4. Review every region in-use.

Note: EBS volume encryption is configured per region.

Expected Result

The CLI should return "EbsEncryptionByDefault": true for every region in use. In the console, Always encrypt new EBS volumes should display Enabled.

Remediation

Using AWS CLI

1. Run:

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

2. Verify that "EbsEncryptionByDefault": true is displayed.
3. Repeat every region requiring the change.

Note: EBS volume encryption is configured per region.

Using AWS Console

1. Login to the EC2 console using https://console.aws.amazon.com/ec2/
2. Under Account attributes, click EBS encryption.
3. Click Manage.
4. Click the Enable checkbox.
5. Click Update EBS encryption.
6. Repeat for every region requiring the change.

Note: EBS volume encryption is configured per region.

Default Value

EBS encryption by default is disabled. It must be explicitly enabled per region.

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/
3. AWS Config rule - ec2_ebs_encryption_by_default

CIS Controls

Profile

Level 1 | Automated