| name | cis-azure-storage-18.2 |
| description | Ensure stored access policies (SAP) are used when generating shared access signature (SAS) tokens |
| category | cis-azure-storage |
| version | 1.0.0 |
| author | cyberstrike-official |
| tags | ["cis","azure","storage","storage-explorer","sas"] |
| cis_id | 18.2 |
| cis_benchmark | CIS Microsoft Azure Storage Services Benchmark v1.0.0 |
| tech_stack | ["azure"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
18.2 Ensure stored access policies (SAP) are used when generating shared access signature (SAS) tokens (Manual)
Description
Use stored access policies (SAP) when generating shared access signature (SAS) tokens in Azure to centrally manage permissions, expiration, and revocation settings for resource access. Stored access policies can be applied to blob containers, file shares, queues, and tables.
Rationale
Stored access policies provide centralized control over SAS token access, allowing administrators to update permissions or revoke access. This approach strengthens security by reducing the risk of unauthorized access to storage resources.
Impact
There is no cost for creating stored access policies, however there is some administrative overhead involved in managing these policies.
Audit Procedure
It is not currently possible to retrieve a list of all generated SAS tokens to check if they were associated with a SAP during creation.
An SAS token that has been created with a SAP will contain an si parameter that references the stored access policy identifier associated with the SAS, e.g. si=<stored-access-policy-identifier>.
The si parameter will be absent from an SAS token created without a SAP.
Expected Result
All SAS tokens should contain the si parameter referencing a stored access policy identifier. SAS tokens without the si parameter are not associated with a stored access policy and are non-compliant.
Remediation
Remediate from Storage Explorer
To create a SAP:
- In Storage Explorer, expand
Storage Accounts.
- Expand a storage account.
- Expand
Blob Containers, File Shares, Queues, or Tables, and right-click a blob container, file share, queue, or table.
- Click
Manage Stored Access Policies....
- Under
Access Policies, click Add.
- Modify the
ID, Start time, Expiry time, and permissions appropriately.
- Click
Save.
- Repeat steps 1-7 as needed to create SAP.
When generating SAS, select a SAP from the Access policy drop-down.
Remediate from Azure Portal
If SAS have been created without a SAP, the SAS can be revoked by regenerating the storage account access keys:
