| name | cis-azure-storage-17.5 |
| description | Ensure that 'Enable Infrastructure Encryption' for Each Storage Account in Azure Storage is Set to 'enabled' |
| category | cis-azure-storage |
| version | 1.0.0 |
| author | cyberstrike-official |
| tags | ["cis","azure","storage","storage-accounts","encryption"] |
| cis_id | 17.5 |
| cis_benchmark | CIS Microsoft Azure Storage Services Benchmark v1.0.0 |
| tech_stack | ["azure"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
17.5 Ensure that 'Enable Infrastructure Encryption' for Each Storage Account in Azure Storage is Set to 'enabled' (Automated)
Description
Enabling encryption at the hardware level on top of the default software encryption for Storage Accounts accessing Azure storage solutions.
Rationale
Azure Storage automatically encrypts all data in a storage account at the network level using 256-bit AES encryption, which is one of the strongest, FIPS 140-2-compliant block ciphers available. Customers who require higher levels of assurance that their data is secure can also enable 256-bit AES encryption at the Azure Storage infrastructure level for double encryption. Double encryption of Azure Storage data protects against a scenario where one of the encryption algorithms or keys may be compromised. Similarly, data is encrypted even before network transmission and in all backups. In this scenario, the additional layer of encryption continues to protect your data. For the most secure implementation of key based encryption, it is recommended to use a Customer Managed asymmetric RSA 2048 Key in Azure Key Vault.
Impact
The read and write speeds to the storage will be impacted if both default encryption and Infrastructure Encryption are checked, as a secondary form of encryption requires more resource overhead for the cryptography of information. This performance impact should be considered in an analysis for justifying use of the feature in your environment. Customer-managed keys are recommended for the most secure implementation, leading to overhead of key management. The key will also need to be backed up in a secure location, as loss of the key will mean loss of the information in the storage.
Audit Procedure
Audit from Azure Portal
- From Azure Portal select the portal menu in the top left.
- Select
Storage Accounts.
- Click on each storage account within each resource group you wish to audit.
- In the overview, under Security, ensure
Infrastructure encryption is set to Enabled.
Audit from Azure CLI
az storage blob show \
--account-name <storage-account> \
--container-name <container> \
--name <blob> \
--query "properties.serverEncrypted"
Audit from PowerShell
$account = Get-AzStorageAccount -ResourceGroupName <resource-group> `
-Name <storage-account>
$blob = Get-AzStorageBlob -Context $account.Context `
-Container <container> `
-Blob <blob>
$blob.ICloudBlob.Properties.IsServerEncrypted
Audit from Azure Policy
Policy ID: 4733ea7b-a883-42fe-8cac-97454c2a9e4a - Name: 'Storage accounts should have infrastructure encryption'
