Google CloudOverview
Google Cloud Key Management Service stores cryptographic keys in a hierarchical structure designed for useful and elegant access control management.
The format for the rotation schedule depends on the client library that is used. For the gcloud command-line tool, the next rotation time must be in ISO or RFC3339 format, and the rotation period must be in the form INTEGER[UNIT], where units can be one of seconds (s), minutes (m), hours (h) or days (d).
Rationale
Set a key rotation period and starting time. A key can be created with a specified rotation period, which is the time between when new key versions are generated automatically. A key can also be created with a specified next rotation time. A key is a named object representing a cryptographic key used for a specific purpose. The key material, the actual bits used for encryption, can change over time as new key versions are created.
A key is used to protect some corpus of data. A collection of files could be encrypted with the same key and people with decrypt permissions on that key would be able to decrypt those files. Therefore, it's necessary to make sure the rotation period is set to a specific time
Impact
After a successful key rotation, the older key version is required in order to decrypt the data encrypted by that previous key version.
Remediation guidance
From Google Cloud Console
- Go to Cryptographic Keys by visiting: https://console.cloud.google.com/security/kms.
- Click on the specific key ring
- From the list of keys, choose the specific key and click on the right side, on the 3 dots.
- Click on
Edit rotation period. - On the pop-up window, select a new rotation period in days which should be less than 90 and then choose the
Starting ondate (date from which the rotation period begins).
Using Google Cloud CLI
Update and schedule rotation for each key:
gcloud kms keys update <keyName> --keyring=<keyRing> --location=<location> --nextrotation-time=<nextRotationTime> --rotation-period=<rotationPeriod>
Default value
By default, KMS encryption keys are rotated every 90 days.
References
- https://cloud.google.com/kms/docs/key-rotation#frequency_of_key_rotation
- https://cloud.google.com/kms/docs/re-encrypt-data
Additional information
Key rotation does NOT re-encrypt already encrypted data with the newly generated key version. If you suspect unauthorized use of a key, you should reencrypt the data protected by that key and then disable or schedule destruction of the prior key version.
It is not recommended to rely solely on irregular rotation, but rather to use irregular rotation if needed in conjunction with a regular rotation schedule.
Multiple Remediation Paths
Google Cloud
SERVICE-WIDE (RECOMMENDED when many resources are affected): Enforce Organization Policies at org/folder level so new resources inherit secure defaults.
gcloud org-policies set-policy policy.yaml
ASSET-LEVEL: Use the product-specific remediation steps above for only the impacted project/resources.
PREVENTIVE: Use org policy constraints/custom constraints and enforce checks in deployment pipelines.
References for Service-Wide Patterns
- GCP Organization Policy overview: https://cloud.google.com/resource-manager/docs/organization-policy/overview
- GCP Organization policy constraints catalog: https://cloud.google.com/resource-manager/docs/organization-policy/org-policy-constraints
- gcloud org-policies: https://cloud.google.com/sdk/gcloud/reference/org-policies
Operational Rollout Workflow
Use this sequence to reduce risk and avoid repeated drift.
1. Contain at Service-Wide Scope First (Recommended)
- Google Cloud: apply organization policy constraints at org/folder scope.
gcloud org-policies set-policy policy.yaml
2. Remediate Existing Affected Assets
- Execute the control-specific Console/CLI steps documented above for each flagged resource.
- Prioritize internet-exposed and production assets first.
3. Validate and Prevent Recurrence
- Re-scan after each remediation batch.
- Track exceptions with owner and expiry date.
- Add preventive checks in IaC/CI pipelines.
Query logic
These are the stored checks tied to this control.
KMS encryption keys are rotated within a period of 90 days
Connectors
Covered asset types
Expected check: eq []
GCP110IAM10{...AssetFragment}
