cyberstrikeus 1.11 Ensure That Separation of Duties Is Enforced While Assigning KMS Related Roles to Users (Automated)
Profile Applicability
- Level 2
Description
It is recommended that the principle of 'Separation of Duties' is enforced while assigning KMS related roles to users.
Rationale
The built-in/predefined IAM role Cloud KMS Admin allows the user/identity to create, delete, and manage service account(s). The built-in/predefined IAM role Cloud KMS CryptoKey Encrypter/Decrypter allows the user/identity (with adequate privileges on concerned resources) to encrypt and decrypt data at rest using an encryption key(s).
The built-in/predefined IAM role Cloud KMS CryptoKey Encrypter allows the user/identity (with adequate privileges on concerned resources) to encrypt data at rest using an encryption key(s). The built-in/predefined IAM role Cloud KMS CryptoKey Decrypter allows the user/identity (with adequate privileges on concerned resources) to decrypt data at rest using an encryption key(s).
Separation of duties is the concept of ensuring that one individual does not have all necessary permissions to be able to complete a malicious action. In Cloud KMS, this could be an action such as using a key to access and decrypt data a user should not normally have access to. Separation of duties is a business control typically used in larger organizations, meant to help avoid security or privacy incidents and errors. It is considered best practice.
No user(s) should have Cloud KMS Admin and any of the Cloud KMS CryptoKey Encrypter/Decrypter, Cloud KMS CryptoKey Encrypter, Cloud KMS CryptoKey Decrypter roles assigned at the same time.
Impact
Removed roles should be assigned to another user based on business needs.
Audit Procedure
From Google Cloud Console
- Go to
IAM & Admin/IAMby visiting: https://console.cloud.google.com/iam-admin/iam - Ensure no member has the roles
Cloud KMS Adminand any of theCloud KMS CryptoKey Encrypter/Decrypter,Cloud KMS CryptoKey Encrypter,Cloud KMS CryptoKey Decrypterassigned.
From Google Cloud CLI
- List all users and role assignments:
gcloud projects get-iam-policy PROJECT_ID
- Ensure that there are no common users found in the member section for roles
cloudkms.adminand any one ofCloud KMS CryptoKey Encrypter/Decrypter,Cloud KMS CryptoKey Encrypter,Cloud KMS CryptoKey Decrypter.
Expected Result
No user should have both Cloud KMS Admin (cloudkms.admin) and any of the CryptoKey Encrypter/Decrypter roles assigned simultaneously.
Remediation
From Google Cloud Console
- Go to
IAM & Admin/IAMusing https://console.cloud.google.com/iam-admin/iam - For any member having
Cloud KMS Adminand any of theCloud KMS CryptoKey Encrypter/Decrypter,Cloud KMS CryptoKey Encrypter,Cloud KMS CryptoKey Decrypterroles granted/assigned, click theDelete Binicon to remove the role from the member.
Note: Removing a role should be done based on the business requirement.
From Google Cloud CLI
Remove the conflicting role from the user:
gcloud projects remove-iam-policy-binding PROJECT_ID --member=user:USER_EMAIL --role=ROLE_TO_REMOVE
Default Value
By default, there are no role assignments that violate separation of duties.
Additional Information
Users granted with Owner (roles/owner) and Editor (roles/editor) have privileges equivalent to Cloud KMS Admin and Cloud KMS CryptoKey Encrypter/Decrypter. To avoid misuse, Owner and Editor roles should be granted to a very limited group of users. Use of these primitive privileges should be minimal.
References
CIS Controls
| Controls Version | Control | IG 1 | IG 2 | IG 3 |
|---|---|---|---|---|
| v8 | 3.3 Configure Data Access Control Lists | x | x | x |
| v7 | 14.6 Protect Information through Access Control Lists | x | x | x |