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

What this check verifies

Azure Storage file shares (SMB) are evaluated for SMB channel encryption and whether the allowed ciphers include the recommended AES-256-GCM. This identifies if encryption is configured and a secure algorithm is present in the SMB settings for file shares within the storage account.

Risk

Missing or weak SMB channel encryption undermines confidentiality and integrity. On-path attackers could read sensitive files, capture hashes, or modify data in transit. Allowing legacy ciphers increases downgrade risks and can facilitate lateral movement, eroding trust boundaries across networks.

Recommendation

Enforce defense in depth by restricting SMB channel encryption to AES-256-GCM on SMB 3.1.1, removing weaker options.
  • Prefer private access (private endpoints/VPN)
  • Require secure transfer and modern TLS
  • Apply least privilege on shares
  • Validate client support and monitor connections during rollout

Remediation

az storage account file-service-properties update —resource-group <resource-group> —account-name <storage-account> —channel-encryption AES-256-GCM

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_channel_encryption_with_secure_algorithm. 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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