Check ID:
Provider: Azure
Service:
Severity: MEDIUM
Categories:
Resource type:
storage_smb_channel_encryption_with_secure_algorithmProvider: Azure
Service:
storageSeverity: MEDIUM
Categories:
encryptionResource type:
microsoft.storage/storageaccountsWhat this check verifies
Azure Storage file shares (SMB) are evaluated for SMB channel encryption and whether the allowed ciphers include the recommendedAES-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 toAES-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
- CLI
- Terraform
- Native IaC
- Dashboard steps
az storage account file-service-properties update —resource-group <resource-group> —account-name <storage-account> —channel-encryption AES-256-GCM
References
- https://www.trendmicro.com/cloudoneconformity/knowledge-base/azure/StorageAccounts/check-for-smb-channel-encryption-type.html
- https://learn.microsoft.com/en-us/azure/storage/files/files-smb-protocol?tabs=azure-portal#smb-security-settings
- https://learn.microsoft.com/en-us/azure/well-architected/service-guides/azure-files#recommendations-for-smb-file-shares
Where this check fires
This check runs on every scheduled scan against your Azure account. Findings appear at Cloud Security → Findings filterable byCheck 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.
← Back to Azure checks