Cis Azure Foundations 9.3.11

Ensure Redundancy is set to 'geo-redundant storage (GRS)' on critical Azure Storage Accounts

Description

Geo-redundant storage (GRS) in Azure replicates data three times within the primary region using locally redundant storage (LRS) and asynchronously copies it to a secondary region hundreds of miles away. This setup ensures high availability and resilience by providing 16 nines (99.99999999999999%) durability over a year, safeguarding data against regional outages.

Rationale

Enabling GRS protects critical data from regional failures by maintaining a copy in a geographically separate location. This significantly reduces the risk of data loss, supports business continuity, and meets high availability requirements for disaster recovery.

Impact

Enabling geo-redundant storage on Azure storage accounts increases costs due to cross-region data replication.

Audit Procedure

Audit from Azure Portal

1. Go to Storage accounts.
2. Click on a storage account.
3. Under Data management, click Redundancy.
4. Ensure that Redundancy is set to Geo-redundant storage (GRS).
5. Repeat steps 1-4 for each storage account.

Audit from Azure CLI

Run the following command to list storage accounts:

az storage account list

For each storage account, run the following command:

az storage account show --resource-group <resource-group> --name <storage-account>

Under sku, ensure that name is set to Standard_GRS.

Audit from PowerShell

Run the following command to list storage accounts:

Get-AzStorageAccount

Run the following command to get the storage account in a resource group with a given name:

$storageAccount = Get-AzStorageAccount -ResourceGroupName <resource-group> -Name <storage-account>

Run the following command to get the redundancy setting for the storage account:

$storageAccount.SKU.Name

Ensure that the command returns Standard_GRS.

Expected Result

sku.name should be Standard_GRS for all critical storage accounts.

Remediation

Remediate from Azure Portal

1. Go to Storage accounts.
2. Click on a storage account.
3. Under Data management, click Redundancy.
4. From the Redundancy drop-down menu, select Geo-redundant storage (GRS).
5. Click Save.
6. Repeat steps 1-5 for each storage account requiring remediation.

Remediate from Azure CLI

For each storage account requiring remediation, run the following command to enable geo-redundant storage:

az storage account update --resource-group <resource-group> --name <storage-account> --sku Standard_GRS

Default Value

The default redundancy setting depends on how the storage account was created and the SKU selected at creation time.

References

1. https://learn.microsoft.com/en-us/azure/storage/common/storage-redundancy
2. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-data-protection

Profile

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