Use a user delegation SAS, account-key SAS tokens cant be revoked without key rotation

TL;DR

If you hand out account-key SAS tokens, have a key rotation plan ready, because that is your only revocation option. Default to user delegation SAS over HTTPS with the least privilege and a short expiry.

Steps

1. If you hand out account-key SAS tokens, have a key rotation plan ready, because that is your only revocation option.
2. Default to user delegation SAS over HTTPS with the least privilege and a short expiry.

When to use

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When not to use

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Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: Microsoft Learn says a user delegation SAS is signed with Microsoft Entra credentials instead of the storage account key, and it is the only SAS type Microsoft recommends. Service SAS and account SAS are signed with the account key, so if one leaks the only way to kill it is rotating the key, which breaks every other token signed with it too. With a user delegation SAS you revoke by revoking the Entra credentials behind the delegation key, and the tokens stop working.

Verified resolution: Default to user delegation SAS over HTTPS with the least privilege and a short expiry. If you hand out account-key SAS tokens, have a key rotation plan ready, because that is your only revocation option.

Source URL: https://learn.microsoft.com/en-us/training/modules/implement-storage-account-security/3-select-authorization-model