Additional Properties Too Permissive

• Query id: 9f88c88d-824d-4d9a-b985-e22977046042
• Query name: Additional Properties Too Permissive
• Platform: OpenAPI
• Severity: Medium
• Category: Insecure Configurations
• URL: Github

Description

Objects should not accept 'additionalProperties' if it is possible
Documentation

Code samples

Code samples with security vulnerabilities

Postitive 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": {
            "schema": {
              "type": "object",
              "properties": {
                "id": {
                  "type": "string"
                },
                "name": {
                  "type": "string"
                }
              },
              "additionalProperties": "true"
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "MyObject": {
        "oneOf": [
          {
            "type": "object",
            "properties": {
              "id": {
                "type": "string"
              },
              "name": {
                "type": "string"
              }
            },
            "additionalProperties": "true"
          },
          {
            "type": "string",
            "additionalProperties": "false"
          }
        ]
      }
    }
  }
}

Postitive 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':
          schema:
            type: object
            properties:
              id:
                type: string
              name:
                type: string
            additionalProperties: 'true'
components:
  schemas:
    MyObject:
      oneOf:
      - type: object
        properties:
          id:
            type: string
          name:
            type: string
        additionalProperties: 'true'
      - type: string
        additionalProperties: 'false'

Postitive test num. 3 - 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": {
            "schema": {
              "type": "object",
              "properties": {
                "id": {
                  "type": "string"
                },
                "name": {
                  "type": "string"
                }
              },
              "additionalProperties": "false"
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "MyObject": {
        "oneOf": [
          {
            "type": "object",
            "properties": {
              "id": {
                "type": "string"
              },
              "name": {
                "type": "string"
              }
            },
            "additionalProperties": "true"
          },
          {
            "type": "string",
            "additionalProperties": "true"
          }
        ]
      }
    }
  }
}

Postitive test num. 4 - 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':
          schema:
            type: object
            properties:
              id:
                type: string
              name:
                type: string
            additionalProperties: 'false'
components:
  schemas:
    MyObject:
      oneOf:
      - type: object
        properties:
          id:
            type: string
          name:
            type: string
        additionalProperties: 'true'
      - type: string
        additionalProperties: 'true'

Postitive test num. 5 - 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": {
            "schema": {
              "type": "object",
              "properties": {
                "id": {
                  "type": "string"
                },
                "name": {
                  "type": "string"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "MyObject": {
        "oneOf": [
          {
            "type": "object",
            "properties": {
              "id": {
                "type": "string"
              },
              "name": {
                "type": "string"
              }
            },
            "additionalProperties": "true"
          },
          {
            "type": "string",
            "additionalProperties": "false"
          }
        ]
      }
    }
  }
}

Postitive test num. 6 - 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':
          schema:
            type: object
            properties:
              id:
                type: string
              name:
                type: string
components:
  schemas:
    MyObject:
      oneOf:
      - type: object
        properties:
          id:
            type: string
          name:
            type: string
        additionalProperties: 'true'
      - type: string
        additionalProperties: 'false'

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": {
            "schema": {
              "type": "object",
              "properties": {
                "id": {
                  "type": "string"
                },
                "name": {
                  "type": "string"
                }
              },
              "additionalProperties": "false"
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "MyObject": {
        "oneOf": [
          {
            "type": "object",
            "properties": {
              "id": {
                "type": "string"
              },
              "name": {
                "type": "string"
              }
            },
            "additionalProperties": "true"
          },
          {
            "type": "string",
            "additionalProperties": "false"
          }
        ]
      }
    }
  }
}

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':
          schema:
            type: object
            properties:
              id:
                type: string
              name:
                type: string
            additionalProperties: 'false'
components:
  schemas:
    MyObject:
      oneOf:
      - type: object
        properties:
          id:
            type: string
          name:
            type: string
        additionalProperties: 'true'
      - type: string
        additionalProperties: 'false'