Using clear-text protocols is security-sensitive

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Clear-text protocols such as ftp, telnet, or http lack encryption of transported data, as well as the capability to build an authenticated connection. It means that an attacker able to sniff traffic from the network can read, modify, or corrupt the transported content. These protocols are not secure as they expose applications to an extensive range of risks:

sensitive data exposure
traffic redirected to a malicious endpoint
malware-infected software update or installer
execution of client-side code
corruption of critical information

Even in the context of isolated networks like offline environments or segmented cloud environments, the insider threat exists. Thus, attacks involving communications being sniffed or tampered with can still happen.

For example, attackers could successfully compromise prior security layers by:

bypassing isolation mechanisms
compromising a component of the network
getting the credentials of an internal IAM account (either from a service account or an actual person)

In such cases, encrypting communications would decrease the chances of attackers to successfully leak data or steal credentials from other network components. By layering various security practices (segmentation and encryption, for example), the application will follow the defense-in-depth principle.

Note that using the http protocol is being deprecated by major web browsers.

In the past, it has led to the following vulnerabilities:

Ask Yourself Whether

Application data needs to be protected against tampering or leaks when transiting over the network.
Application data transits over an untrusted network.
Compliance rules require the service to encrypt data in transit.
OS-level protections against clear-text traffic are deactivated.

There is a risk if you answered yes to any of those questions.

Recommended Secure Coding Practices

Make application data transit over a secure, authenticated and encrypted protocol like TLS or SSH. Here are a few alternatives to the most common clear-text protocols:
- Use sftp, scp, or ftps instead of ftp.
- Use https instead of http.

It is recommended to secure all transport channels, even on local networks, as it can take a single non-secure connection to compromise an entire application or system.

Sensitive Code Example

For Microsoft.Web/sites:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Web/sites",
      "name": "example",
      "apiVersion": "2022-09-01",
      "properties": {
        "httpsOnly": false
      }
    }
  ]
}

resource symbolicname 'Microsoft.Web/sites@2022-03-01' = {
  properties: {
    httpsOnly: false // Sensitive
  }
}

For Microsoft.Web/sites/config:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Web/sites/config",
      "name": "sites/example",
      "apiVersion": "2022-09-01",
      "properties": {
        "ftpsState": "AllAllowed"
      }
    }
  ]
}

resource symbolicname 'Microsoft.Web/sites/config@2022-09-01' = {
  properties: {
    ftpsState: 'AllAllowed' // Sensitive
  }
}

For Microsoft.Storage/storageAccounts:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Storage/storageAccounts",
      "name": "example",
      "apiVersion": "2022-09-01",
      "properties": {
        "supportsHttpsTrafficOnly": false
      }
    }
  ]
}

resource symbolicname 'Microsoft.Storage/storageAccounts@2022-09-01' = {
  properties: {
    supportsHttpsTrafficOnly: false // Sensitive
  }
}

For Microsoft.ApiManagement/service/apis:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.ApiManagement/service/apis",
      "name": "service/example",
      "apiVersion": "2022-08-01",
      "properties": {
        "protocols": ["http"]
      }
    }
  ]
}

resource symbolicname 'Microsoft.ApiManagement/service/apis@2022-08-01' = {
  properties: {
    protocols: ['http'] // Sensitive
  }
}

For Microsoft.Cdn/profiles/endpoints:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Cdn/profiles/endpoints",
      "name": "profiles/example",
      "apiVersion": "2021-06-01",
      "properties": {
        "isHttpAllowed": true
      }
    }
  ]
}

resource symbolicname 'Microsoft.Cdn/profiles/endpoints@2021-06-01' = {
  properties: {
    isHttpAllowed: true // Sensitive
  }
}

For Microsoft.Cache/redisEnterprise/databases:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Cache/redisEnterprise/databases",
      "name": "redisEnterprise/example",
      "apiVersion": "2022-01-01",
      "properties": {
        "clientProtocol": "Plaintext"
      }
    }
  ]
}

resource symbolicname 'Microsoft.Cache/redisEnterprise/databases@2022-01-01' = {
  properties: {
    clientProtocol: 'Plaintext' // Sensitive
  }
}

For Microsoft.DBforMySQL/servers, Microsoft.DBforMariaDB/servers, and Microsoft.DBforPostgreSQL/servers:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.DBforMySQL/servers",
      "name": "example",
      "apiVersion": "2017-12-01",
      "properties": {
        "sslEnforcement": "Disabled"
      }
    }
  ]
}

resource symbolicname 'Microsoft.DBforMySQL/servers@2017-12-01' = {
  properties: {
    sslEnforcement: 'Disabled' // Sensitive
  }
}

Compliant Solution

For Microsoft.Web/sites:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Web/sites",
      "name": "example",
      "apiVersion": "2022-09-01",
      "properties": {
        "httpsOnly": true
      }
    }
  ]
}

resource symbolicname 'Microsoft.Web/sites@2022-03-01' = {
  properties: {
    httpsOnly: true
  }
}

For Microsoft.Web/sites/config:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Web/sites/config",
      "name": "sites/example",
      "apiVersion": "2022-09-01",
      "properties": {
        "ftpsState": "FtpsOnly"
      }
    }
  ]
}

resource symbolicname 'Microsoft.Web/sites/config@2022-09-01' = {
  properties: {
    ftpsState: 'FtpsOnly'
  }
}

For Microsoft.Storage/storageAccounts:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Storage/storageAccounts",
      "name": "example",
      "apiVersion": "2022-09-01",
      "properties": {
        "supportsHttpsTrafficOnly": true
      }
    }
  ]
}

resource symbolicname 'Microsoft.Storage/storageAccounts@2022-09-01' = {
  properties: {
    supportsHttpsTrafficOnly: true
  }
}

For Microsoft.ApiManagement/service/apis:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.ApiManagement/service/apis",
      "name": "service/example",
      "apiVersion": "2022-08-01",
      "properties": {
        "protocols": ["https"]
      }
    }
  ]
}

resource symbolicname 'Microsoft.ApiManagement/service/apis@2022-08-01' = {
  properties: {
    protocols: ['https']
  }
}

For Microsoft.Cdn/profiles/endpoints:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Cdn/profiles/endpoints",
      "name": "profiles/example",
      "apiVersion": "2021-06-01",
      "properties": {
        "isHttpAllowed": false
      }
    }
  ]
}

resource symbolicname 'Microsoft.Cdn/profiles/endpoints@2021-06-01' = {
  properties: {
    isHttpAllowed: false
  }
}

For Microsoft.Cache/redisEnterprise/databases:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Cache/redisEnterprise/databases",
      "name": "redisEnterprise/example",
      "apiVersion": "2022-01-01",
      "properties": {
        "clientProtocol": "Encrypted"
      }
    }
  ]
}

resource symbolicname 'Microsoft.Cache/redisEnterprise/databases@2022-01-01' = {
  properties: {
    clientProtocol: 'Encrypted'
  }
}

For Microsoft.DBforMySQL/servers, Microsoft.DBforMariaDB/servers, and Microsoft.DBforPostgreSQL/servers:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.DBforMySQL/servers",
      "name": "example",
      "apiVersion": "2017-12-01",
      "properties": {
        "sslEnforcement": "Enabled"
      }
    }
  ]
}

resource symbolicname 'Microsoft.DBforMySQL/servers@2017-12-01' = {
  properties: {
    sslEnforcement: 'Enabled'
  }
}

See

Documentation

AWS Documentation - Listeners for your Application Load Balancers
AWS Documentation - Stream Encryption

Articles & blog posts

Google - Moving towards more secure web
Mozilla - Deprecating non secure http

Standards

CWE - CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
CWE - CWE-319 - Cleartext Transmission of Sensitive Information
STIG Viewer - Application Security and Development: V-222397 - The application must implement cryptographic mechanisms to protect the integrity of remote access sessions.
STIG Viewer - Application Security and Development: V-222534 - Service-Oriented Applications handling non-releasable data must authenticate endpoint devices via mutual SSL/TLS.
STIG Viewer - Application Security and Development: V-222562 - Applications used for non-local maintenance must implement cryptographic mechanisms to protect the integrity of maintenance and diagnostic communications.
STIG Viewer - Application Security and Development: V-222563 - Applications used for non-local maintenance must implement cryptographic mechanisms to protect the confidentiality of maintenance and diagnostic communications.
STIG Viewer - Application Security and Development: V-222577 - The application must not expose session IDs.
STIG Viewer - Application Security and Development: V-222596 - The application must protect the confidentiality and integrity of transmitted information.
STIG Viewer - Application Security and Development: V-222597 - The application must implement cryptographic mechanisms to prevent unauthorized disclosure of information and/or detect changes to information during transmission.
STIG Viewer - Application Security and Development: V-222598 - The application must maintain the confidentiality and integrity of information during preparation for transmission.
STIG Viewer - Application Security and Development: V-222599 - The application must maintain the confidentiality and integrity of information during reception.

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