cyberstrikeus 2.1.1.2 Ensure that shared access signature (SAS) tokens expire within an hour (Manual)
Description
Shared access signature (SAS) tokens provide restricted access to Azure Storage resources (such as blobs, files, queues, or tables) for a defined time period with specific permissions. It enables users to interact with the resources without exposing account keys, offering precise control over the permitted actions (e.g., read, write) and the duration of access. To minimize security risks, SAS tokens should be configured with the shortest possible lifespan, ideally lasting no longer than an hour.
Rationale
A short lifespan for SAS tokens is recommended to minimize the risk of unauthorized access. SAS tokens grant time-limited access to resources, and a longer duration increases the opportunity for misuse if the token is compromised. By setting a shorter lifespan, the potential for security breaches is reduced.
Impact
SAS can pose security risks if they are not managed carefully.
Audit Procedure
This is a Common Reference Recommendation. Audit and remediation procedures with full details will be found in the section dedicated to each specific service where this recommendation applies:
- Azure Blob Storage
- Queue Storage
- Storage Accounts > Secrets and Keys
- Storage Explorer
Expected Result
SAS tokens should have an expiration time of no more than 1 hour from creation.
Remediation
This is a Common Reference Recommendation. Audit and remediation procedures with full details will be found in the section dedicated to each specific service where this recommendation applies:
- Azure Blob Storage
- Queue Storage
- Storage Accounts > Secrets and Keys
- Storage Explorer
Default Value
By default, expiration for shared access signature is set to 8 hours.
References
- https://docs.microsoft.com/en-us/azure/storage/common/storage-sas-overview
- https://docs.microsoft.com/en-us/rest/api/storageservices/delegating-access-with-a-shared-access-signature
Additional Information
This recommendation forms the basis for the recommendations with the same title in the following sections:
- Azure Blob Storage
- Queue Storage
- Storage Accounts > Secrets and Keys
- Storage Explorer
CIS Controls
| Controls Version | Control | IG 1 | IG 2 | IG 3 |
|---|---|---|---|---|
| v8 | 6.2 Establish an Access Revoking Process - Establish and follow a process, preferably automated, for revoking access to enterprise assets, through disabling accounts immediately upon termination, rights revocation, or role change of a user. Disabling accounts, instead of deleting accounts, may be necessary to preserve audit trails. | x | x | x |
| v7 | 16.7 Establish Process for Revoking Access - Establish and follow an automated process for revoking system access by disabling accounts immediately upon termination or change of responsibilities of an employee or contractor. Disabling these accounts, instead of deleting accounts, allows preservation of audit trails. | x | x |
Profile
Level 1 | Manual