JSON '$ref' alongside other properties (v3)

• Query id: 96beb800-566f-49a9-a0ea-dbdf4bc80429
• Query name: JSON '$ref' alongside other properties (v3)
• Platform: OpenAPI
• Severity: Info
• Category: Best Practices
• CWE: 710
• URL: Github

Description

Each field on Open API specification which accepts '$ref', infers that field is using a reference object, which has only '$ref' key
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - json file

{
  "openapi": "3.0.0",
  "info": {
    "title": "Simple API Overview",
    "version": "1.0.0"
  },
  "paths": {
    "/": {
      "get": {
        "operationId": "listVersionsv2",
        "summary": "List API versions",
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "type": "integer",
                  "$ref": "#/components/schemas/MyObject"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "MyObject": {
        "type": "object",
        "properties": {
          "id": {
            "type": "string"
          },
          "name": {
            "type": "string"
          }
        }
      }
    }
  }
}

Positive test num. 2 - yaml file

openapi: 3.0.0
info:
  title: Simple API Overview
  version: 1.0.0
paths:
  "/":
    get:
      operationId: listVersionsv2
      summary: List API versions
      responses:
        "200":
          description: 200 response
          content:
            application/json:
              schema:
                type: integer
                "$ref": "#/components/schemas/MyObject"
components:
  schemas:
    MyObject:
      type: object
      properties:
        id:
          type: string
        name:
          type: string

Positive test num. 3 - json file

{
  "swagger": "2.0",
  "info": {
    "title": "Simple API Overview",
    "version": "1.0.0"
  },
  "paths": {
    "/": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/User",
              "description": "schema"
            }
          }
        },
        "operationId": "listVersionsv2",
        "summary": "List API versions"
      }
    }
  },
  "definitions": {
    "User": {
      "properties": {
        "id": {
          "type": "integer"
        },
        "name": {
          "type": "string"
        }
      },
      "required": [
        "id",
        "name"
      ]
    }
  }
}

Positive test num. 4 - yaml file

swagger: "2.0"
info:
  title: Simple API Overview
  version: 1.0.0
paths:
  "/":
    get:
      operationId: listVersionsv2
      summary: List API versions
      responses:
        "200":
          description: 200 response
          schema:
            $ref: "#/definitions/User"
            description: schema
definitions:
  User:
    properties:
      id:
        type: integer
      name:
        type: string
    required:
      - id
      - name

Code samples without security vulnerabilities

Negative test num. 1 - json file

{
  "openapi": "3.0.0",
  "info": {
    "title": "Simple API Overview",
    "version": "1.0.0"
  },
  "paths": {
    "/": {
      "get": {
        "operationId": "listVersionsv2",
        "summary": "List API versions",
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/MyObject"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "MyObject": {
        "type": "object",
        "properties": {
          "id": {
            "type": "string"
          },
          "name": {
            "type": "string"
          }
        }
      }
    }
  }
}

Negative test num. 2 - yaml file

openapi: 3.0.0
info:
  title: Simple API Overview
  version: 1.0.0
paths:
  "/":
    get:
      operationId: listVersionsv2
      summary: List API versions
      responses:
        "200":
          description: 200 response
          content:
            application/json:
              schema:
                "$ref": "#/components/schemas/MyObject"
components:
  schemas:
    MyObject:
      type: object
      properties:
        id:
          type: string
        name:
          type: string

Negative test num. 3 - json file

{
  "swagger": "2.0",
  "info": {
    "title": "Simple API Overview",
    "version": "1.0.0"
  },
  "paths": {
    "/": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/User"
            }
          }
        },
        "operationId": "listVersionsv2",
        "summary": "List API versions"
      }
    }
  },
  "definitions": {
    "User": {
      "properties": {
        "id": {
          "type": "integer"
        },
        "name": {
          "type": "string"
        }
      },
      "required": [
        "id",
        "name"
      ]
    }
  }
}

Negative test num. 4 - yaml file

swagger: "2.0"
info:
  title: Simple API Overview
  version: 1.0.0
paths:
  "/":
    get:
      operationId: listVersionsv2
      summary: List API versions
      responses:
        "200":
          description: 200 response
          schema:
            $ref: "#/definitions/User"
definitions:
  User:
    properties:
      id:
        type: integer
      name:
        type: string
    required:
      - id
      - name