lacework-global-532
3.7 Ensure that 'Public access level' is disabled for storage accounts with blob containers (Automated)
Profile Applicability
• Level 1
Description
Disallowing public access for a storage account overrides the public access settings for individual containers in that storage account.
Rationale
The default configuration for a storage account permits a user with appropriate permissions to configure public (anonymous) access to containers and blobs in a storage account. Keep in mind that public access to a container is always turned off by default and must be explicitly configured to permit anonymous requests. It grants read-only access to these resources without sharing the account key, and without requiring a shared access signature. It is recommended not to provide anonymous access to blob containers until, and unless, it is strongly desired. A shared access signature token or Azure AD RBAC should be used for providing controlled and timed access to blob containers. If no anonymous access is needed on any container in the storage account, it’s recommended to set allowBlobPublicAccess false at the account level, which forbids any container to accept anonymous access in the future.
Impact
Access will have to be managed using shared access signatures or via Azure AD RBAC.
Audit
From Azure Console
- Go to
Storage Accounts
- For each storage account, go to the 'Configuration' setting under 'Settings'
- Check if Blob public access is Disabled.
From Azure CLI
Ensure allowBlobPublicAccess is false
az storage account show --name <storage-account> --resource-group <resource-group> --query allowBlobPublicAccess --output tsv
Remediation
From Azure Console
First, follow Microsoft documentation and create shared access signature tokens for your blob containers. Then,
- Go to
Storage Accounts
- For each storage account, go to
Allow Blob public access
in Configuration - Set
Disabled
if no anonymous access is needed on the storage account
Alternatively, if some containers must be made public (so 'Allow Blob public access' is enabled) ,
- For each storage account, go to
Containers
under theData Storage
heading - For each private container, click
Access policy
- Set
Public access level
toPrivate (no anonymous access)
From Azure CLI
First, follow Microsoft documentation and created shared access signature tokens for your blob containers. Then, if no anonymous access is wanted (as recommended here),
- Set 'Allow Blob Public Access' to false on the storage account
az storage account update --name <storage-account> --resource-group <resource-group> --allow-blob-public-access false
Alternatively, if some containers must be made public (so 'Allow Blob public access' is enabled) ,
- Identify the container name from the audit command
- Set the permission for public access to
private
(off) for the above container name, using the below command
az storage container set-permission --name <containerName> --public-access off --account-name <accountName> --account-key <accountKey>
References
https://docs.microsoft.com/en-us/azure/storage/blobs/storage-manage-access-to-resources
https://docs.microsoft.com/en-us/azure/storage/blobs/anonymous-read-access-prevent
https://docs.microsoft.com/en-us/security/benchmark/azure/security-controls-v3-governance-strategy#gs-2-define-and-implement-enterprise-segmentationseparation-of-duties-strategy
https://docs.microsoft.com/en-us/security/benchmark/azure/security-controls-v3-network-security#ns-2-secure-cloud-services-with-network-controls
https://docs.microsoft.com/en-us/azure/storage/blobs/anonymous-read-access-configure
https://docs.microsoft.com/en-us/azure/storage/blobs/assign-azure-role-data-access