Control: 8.8 Ensure Automatic Key Rotation is Enabled Within Azure Key Vault for the Supported Services

Description

Automatic Key Rotation is available in Public Preview. The currently supported applications are Key Vault, Managed Disks, and Storage accounts accessing keys within Key Vault. The number of supported applications will incrementally increased.

Once set up, Automatic Private Key Rotation removes the need for manual administration when keys expire at intervals determined by your organization's policy. The recommended key lifetime is 2 years. Your organization should determine its own key expiration policy.

Remediation

Note: Azure CLI and Powershell use ISO8601 flags to input timespans. Every timespan input will be in the format P<timespanInISO8601Format>(Y,M,D). The leading P is required with it denoting period. The (Y,M,D) are for the duration of Year, Month,and Day respectively. A time frame of 2 years, 2 months, 2 days would be (P2Y2M2D).

From Azure Portal

From Azure Portal select the Portal Menu in the top left.
Select Key Vaults.
Select the Key Vault you wish t oaudit.
Under the Settings heading select Keys.
Select the key you wish to audit within this vault and repeat the next steps for each.
In the top row select Rotation policy.
Next to Set key rotation policy select the link Not Configured.
Select the Expiry Time in for your need.
In this menu select Enable in the row Enable auto rotation
Set the Rotation Option to Automatically renew.. To automatically rotate keys, set the rotation time to or near the Expiry Time.
If desired set the Notification duration to a duration before the expiration.

From Azure CLI

Run the following command for each key to update its policy to be auto-rotated:

az keyvault key rotation-policy update -n <keyName> --vault-name <vaultName> --value <path/to/policy.json>

Note: It is easiest to supply the policy flags in a .json file. An example
json file would be:

{
 "lifetimeActions": [
  {
    "trigger": {
    "timeAfterCreate": "<timespanInISO8601Format>",
    "timeBeforeExpiry" : null
    },
    "action": {
    "type": "Rotate"
    }
  },
  {
    "trigger": {
    "timeBeforeExpiry" : "<timespanInISO8601Format>"
    },
    "action": {
    "type": "Notify"
    }
  }
 ],
  "attributes": {
  "expiryTime": "<timespanInISO8601Format>"
  }
}

From Powershell

Run the following command for each key to update its policy:

Set-AzKeyVaultKeyRotationPolicy -VaultName test-kv -Name test-key -PolicyPath
rotation_policy.json

Note: It is easiest to supply the policy flags in a .json file. An example json file would be:

<#
rotation_policy.json
{
 "lifetimeActions": [
  {
    "trigger": {
    "timeAfterCreate": "P<timespanInISO8601Format>M",
    "timeBeforeExpiry": null
    },
    "action": {
    "type": "Rotate"
    }
  },
  {
    "trigger": {
    "timeBeforeExpiry": "P<timespanInISO8601Format>D"
    },
    "action": {
    "type": "Notify"
    }
  }
 ],
  "attributes": {
  "expiryTime": "P<timespanInISO8601Format>Y"
  }
}
#>

Default Value:

By default, Automatic Key Rotation is not enabled.

Usage

Run the control in your terminal:

powerpipe control run azure_compliance.control.cis_v150_8_8

Snapshot and share results via Turbot Pipes:

powerpipe login
powerpipe control run azure_compliance.control.cis_v150_8_8 --share

SQL

This control uses a named query:

with key_rotation_policy as (
  select
    id
  from
    azure_key_vault_key,
    jsonb_array_elements(rotation_policy -> 'lifetimeActions') as lifetimeActions
  where
    lifetimeActions -> 'action' ->> 'type' = 'Rotate'
    and lifetimeActions -> 'trigger' -> 'timeAfterCreate' is not null
)
select
  kvk.id as resource,
  case
    when p.id is not null then 'ok'
    else 'alarm'
  end as status,
  case
    when p.id is not null then vault_name || ' key ' || kvk.name || ' automatic rotation enabled.'
    else vault_name || ' key ' || kvk.name || ' automatic rotation disabled.'
  end as reason
  
  , kvk.resource_group as resource_group
  , sub.display_name as subscription
from
  azure_key_vault_key kvk
  left join key_rotation_policy as p on p.id = kvk.id
  left join azure_subscription sub on sub.subscription_id = kvk.subscription_id;