Check ID: storage_smb_protocol_version_is_latest
Provider: Azure
Service: storage
Severity: MEDIUM
Categories: vulnerabilities
Resource type: microsoft.storage/storageaccounts

What this check verifies

Azure Storage file shares (SMB) are configured to allow only the latest SMB protocol version, blocking legacy SMB versions at the storage account level

Risk

Allowing legacy SMB versions enables protocol downgrade and weak cipher negotiation, reducing confidentiality and integrity. Adversaries can intercept or alter traffic, bypass strong signing/encryption, and exploit known flaws for lateral movement or credential replay

Recommendation

Restrict SMB to the newest version (e.g., SMB 3.1.1) and disable older versions. Enforce encryption in transit and prefer Kerberos over NTLM. Validate client compatibility, apply least privilege on shares, and monitor access to maintain defense in depth

Remediation

az storage account file-service-properties update —resource-group <RESOURCE_GROUP> —account-name <STORAGE_ACCOUNT_NAME> —versions SMB3.1.1

References

Where this check fires

This check runs on every scheduled scan against your Azure account. Findings appear at Cloud Security → Findings filterable by Check ID = storage_smb_protocol_version_is_latest. To re-evaluate after a fix, hit Run now on the account’s schedule under Cloud Security → Schedules — the next scan re-checks this control and marks the finding fixed or keeps it persistent.
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