Description

The root user account is the most privileged user in an AWS account. MFA adds an extra layer of protection on top of a user name and password. With MFA enabled, when a user signs in to an AWS website, they are prompted for their user name and password as well as an authentication code from their AWS MFA device. For Level 2, it is recommended that the root user account be protected with a hardware MFA device.

Rationale

A hardware MFA has a smaller attack surface than a virtual MFA. For example, a hardware MFA does not inherit the attack surface of the mobile smartphone on which a virtual MFA resides.

Note: Using hardware MFA for many AWS accounts may create a logistical device management issue. If this is the case, consider implementing this Level 2 recommendation selectively for the highest-security AWS accounts and applying the Level 1 recommendation to the remaining accounts.

Audit

Perform the following to determine if the root user account has a hardware MFA setup:

1. Run the following command to determine if the root account has MFA setup:

   aws iam get-account-summary | grep "AccountMFAEnabled"

   The AccountMFAEnabled property set to 1 indicates that the root user account has MFA (virtual or hardware) enabled.

   AccountPasswordPresent set to 0 indicates that the root console credential has been removed.

   If the AccountMFAEnabled property is set to 0 and AccountPasswordPresent is set to 1, the account is not compliant with this recommendation.

2. If the AccountMFAEnabled property is set to 1, determine whether the root account has hardware MFA enabled.

   Run the following command to list all virtual MFA devices:

   aws iam list-virtual-mfa-devices

   If the output contains one MFA with the following Serial Number, it means the MFA is virtual, not hardware, and the account is not compliant with this recommendation: "SerialNumber": "arn:aws:iam::_<aws_account_number>_:mfa/root-account-mfa-device".

References

1. CCE-78911-5
2. https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_mfa_enable_virtual.html
3. https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_mfa_enable_physical.html#enable-hw-mfa-for-root

Additional Information

The IAM root user for us-gov cloud regions does not have console access. This control is not applicable for us-gov cloud regions.