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App Service minimum TLS version#

Security · App Service · 2020_06

App Service should reject TLS versions older than 1.2.

Description#

The minimum version of TLS that Azure App Service accepts is configurable. Older TLS versions are no longer considered secure by industry standards, such as PCI DSS.

App Service lets you disable outdated protocols and enforce TLS 1.2. By default, a minimum of TLS 1.2 is enforced.

Recommendation#

Consider configuring the minimum supported TLS version to be 1.2. Also consider using Azure Policy to audit or enforce this configuration.

Examples#

Configure with Azure template#

To deploy App Services that pass this rule:

  • Set properties.siteConfig.minTlsVersion to 1.2.

For example:

Azure Template snippet
{
    "type": "Microsoft.Web/sites",
    "apiVersion": "2021-02-01",
    "name": "[parameters('name')]",
    "location": "[parameters('location')]",
    "kind": "web",
    "properties": {
        "serverFarmId": "[resourceId('Microsoft.Web/serverfarms', parameters('planName'))]",
        "httpsOnly": true,
        "siteConfig": {
            "alwaysOn": true,
            "minTlsVersion": "1.2",
            "ftpsState": "FtpsOnly",
            "remoteDebuggingEnabled": false,
            "http20Enabled": true
        }
    },
    "tags": "[parameters('tags')]",
    "dependsOn": [
        "[resourceId('Microsoft.Web/serverfarms', parameters('planName'))]"
    ]
}

Configure with Bicep#

To deploy App Services that pass this rule:

  • Set properties.siteConfig.minTlsVersion to 1.2.

For example:

Azure Bicep snippet
resource webApp 'Microsoft.Web/sites@2021-02-01' = {
  name: name
  location: location
  kind: 'web'
  properties: {
    serverFarmId: appPlan.id
    httpsOnly: true
    siteConfig: {
      alwaysOn: true
      minTlsVersion: '1.2'
      ftpsState: 'FtpsOnly'
      remoteDebuggingEnabled: false
      http20Enabled: true
    }
  }
  tags: tags
}
Last update: 2022-10-17

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