Transporting access tokens as cleartext allowed

Description

One or more global security schemes in the API allows to set security requirements that accept access tokens sent in cleartext over an unencrypted channel. Attackers can easily intercept API calls and retrieve the tokens. They can then use the tokens to make other API calls.

This is a potential risk, because the definition is done on the global level. However, it easily turns into an actual risk when the unsafe method is used in a security requirement or operation.

For more details, see the OpenAPI Specification.

Example

The following is an example of how this type of risk could look in your API definition:

"schemes": [
    "http"
  ],
  ...
  "securityDefinitions": {
    "OAuth2": {
      "type": "oauth2",
      "flow": "accessCode",
      "scopes": {
        "readOnly": "read objects in your account"
      },
      "authorizationUrl": "https://example.com/oauth/authorize",
      "tokenUrl": "https://example.com/oauth/token", 
    }
  },
  ...
  "security" : [
    {"OAuth2": [ "readOnly" ]
    }
  ]
}

Possible exploit scenario

Attackers can intercept the credentials simply by listening to the network traffic in a public WiFi network. They could also use a traffic logging tool on a smartphone, computer, or browser, or sniff the traffic in the network to get the credentials.

Remediation

Set schemes to support HTTPS only so that all traffic is encrypted.

            ...
  "schemes": [
    "https"
  ],
  ...
  "securityDefinitions": {
    "OAuth2": {
      "type": "oauth2",
      "flow": "accessCode",
      "scopes": {
        "readOnly": "read objects in your account"
      },
      "authorizationUrl": "https://example.com/oauth/authorize",
      "tokenUrl": "https://example.com/oauth/token", 
    }
  },
  ...
  "security" : [
    "OAuth2": [ "readOnly" ]
  ]
}